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WO2011136266A1 - Système de communication d'unité mobile - Google Patents

Système de communication d'unité mobile Download PDF

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Publication number
WO2011136266A1
WO2011136266A1 PCT/JP2011/060257 JP2011060257W WO2011136266A1 WO 2011136266 A1 WO2011136266 A1 WO 2011136266A1 JP 2011060257 W JP2011060257 W JP 2011060257W WO 2011136266 A1 WO2011136266 A1 WO 2011136266A1
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WO
WIPO (PCT)
Prior art keywords
cell
local enb
mobile terminal
base station
enb
Prior art date
Application number
PCT/JP2011/060257
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English (en)
Japanese (ja)
Inventor
勇次 掛樋
美保 前田
満 望月
靖 岩根
正幸 中澤
大成 末満
Original Assignee
三菱電機株式会社
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Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to JP2012512881A priority Critical patent/JP5490227B2/ja
Publication of WO2011136266A1 publication Critical patent/WO2011136266A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/02—Power saving arrangements
    • H04W52/0209—Power saving arrangements in terminal devices
    • H04W52/0212—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave
    • H04W52/0216—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave using a pre-established activity schedule, e.g. traffic indication frame
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W68/00—User notification, e.g. alerting and paging, for incoming communication, change of service or the like
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the present invention relates to a mobile communication system that performs wireless communication between a plurality of mobile terminals and a base station.
  • the W-CDMA Wideband Code Division Multiple Access
  • HS-DSCH High-Speed-Downlink Shared Channel
  • HSDPA High-Speed-Downlink-Packet-Access
  • HSUPA High-Speed-Uplink-Packet-Access
  • W-CDMA uses code division multiple access (Code-Division-Multiple-Access)
  • LTE uses OFDM (Orthogonal Frequency-Division-Multiplexing) in the downlink direction and SC-FDMA (Single in the uplink direction).
  • Code-Division-Multiple-Access code division multiple access
  • LTE uses OFDM (Orthogonal Frequency-Division-Multiplexing) in the downlink direction and SC-FDMA (Single in the uplink direction).
  • SC-FDMA Single in the uplink direction.
  • a communication system is configured using a new core network different from the general packet radio service (GPRS), which is a core network of W-CDMA, and therefore, as an independent radio access network different from the W-CDMA network.
  • GPRS general packet radio service
  • a base station that communicates with a mobile terminal (User Equipment: UE)
  • eNB E-UTRAN NodeB
  • a base station controller Radio Network Controller
  • EPC Evolved Packet Core
  • GW Access Gateway
  • a unicast service and an E-MBMS service (Evolved Multimedia Broadcast Multicast Service) are provided.
  • the E-MBMS service is a broadcast-type multimedia service and may be simply referred to as MBMS. Mass broadcast contents such as news, weather forecasts, and mobile broadcasts are transmitted to a plurality of mobile terminals. This is also called a point-to-multipoint service.
  • Non-Patent Document 1 (Chapter 4.6.1) describes the current decisions regarding the overall architecture of the LTE system in 3GPP. The overall architecture will be described with reference to FIG. FIG. 1 is an explanatory diagram illustrating a configuration of an LTE communication system.
  • a control protocol for the mobile terminal 101 such as RRC (Radio Resource Control) and a user plane such as PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), PHY (Physical Layer) E-UTRAN (Evolved102Universal Terrestrial Radio Access) is composed of one or more base stations 102.
  • RRC Radio Resource Control
  • PDCP Packet Data Convergence Protocol
  • RLC Radio Link Control
  • MAC Medium Access Control
  • PHY Physical Layer
  • E-UTRAN Evolved102Universal Terrestrial Radio Access
  • the base station 102 performs scheduling (scheduling) and transmission of a paging signal (also called a paging message or paging message) notified from an MME (Mobility Management Entity) 103.
  • Base stations 102 are connected to each other via an X2 interface.
  • the base station 102 is connected to an EPC (Evolved Packet Core) via an S1 interface. More specifically, the base station 102 is connected to an MME (Mobility Management Entity) 103 via an S1_MME interface, and is connected to an S-GW (Serving Gateway) 104 via an S1_U interface.
  • EPC Evolved Packet Core
  • the MME 103 distributes a paging signal to a plurality or a single base station 102. Further, the MME 103 performs mobility control (Mobility control) in a standby state (Idle State). The MME 103 manages a tracking area (Tracking Area) list when the mobile terminal is in a standby state and in an active state (Active State).
  • Mobility control mobility control
  • Idle State standby state
  • the MME 103 manages a tracking area (Tracking Area) list when the mobile terminal is in a standby state and in an active state (Active State).
  • the S-GW 104 transmits / receives user data to / from one or a plurality of base stations 102.
  • the S-GW 104 becomes a local mobility anchor point (Mobility Anchor Point) during handover between base stations.
  • the EPC further includes a P-GW (PDN Gateway), which performs packet filtering and UE-ID address allocation for each user.
  • PDN Gateway PDN Gateway
  • the control protocol RRC between the mobile terminal 101 and the base station 102 performs broadcast, paging, RRC connection management (RRC connection management), and the like.
  • RRC connection management There are RRC_IDLE and RRC_CONNECTED as states of the base station and the mobile terminal in RRC.
  • RRC_IDLE PLMN (Public Land Mobile Mobile Network) selection, system information (System Information: SI) notification, paging, cell re-selection, mobility, and the like are performed.
  • RRC_CONNECTED a mobile terminal has an RRC connection (connection), can transmit and receive data to and from the network, and performs handover (Handover: HO), measurement of a neighbor cell (Neighbour cell), and the like.
  • RRC_IDLE is also simply referred to as IDLE or standby state.
  • RRC_CONNECTED is also simply referred to as CONNECTED or connection state.
  • the “standby state” refers to a state in which power is turned on but not connected to the base station, in other words, a state in which power is on and communication is not performed.
  • the “connection state” means a state in which the base station is connected, in other words, a communication state, and corresponds to the “active state” described above.
  • Non-Patent Document 1 (Chapter 5) describes the current decisions regarding the frame configuration in the LTE system in 3GPP, with reference to FIG.
  • FIG. 2 is an explanatory diagram showing a configuration of a radio frame used in the LTE communication system.
  • one radio frame (Radio frame) is 10 ms.
  • the radio frame is divided into ten equally sized subframes.
  • the subframe is divided into two equally sized slots.
  • a downlink synchronization signal (Downlink Synchronization Signal: SS) is included in the first and sixth subframes for each radio frame.
  • the synchronization signal includes a first synchronization signal (Primary Synchronization Signal: P-SS) and a second synchronization signal (Secondary Synchronization Signal: S-SS).
  • MBSFN subframe For each subframe, multiplexing of a channel for MBSFN (Multimedia broadcast multicast service Single Frequency Network) and a channel for other than MBSFN is performed.
  • MBSFN subframe a subframe for MBSFN transmission
  • MBSFN subframe MBSFN subframe
  • Non-Patent Document 2 describes a signaling example at the time of MBSFN subframe allocation.
  • FIG. 3 is an explanatory diagram showing the configuration of the MBSFN frame.
  • an MBSFN subframe is allocated for each MBSFN frame (MBSFN frame).
  • a set of MBSFN frames (MBSFN frame Cluster) is scheduled.
  • a repetition period (Repetition Period) of a set of MBSFN frames is assigned.
  • Non-Patent Document 1 (Chapter 5) describes the current decisions regarding the channel configuration in the LTE system in 3GPP. It is assumed that the CSG cell (ClosednSubscriber Group ⁇ ⁇ ⁇ ⁇ cell) uses the same channel configuration as the non-CSG cell.
  • a physical channel will be described with reference to FIG.
  • FIG. 4 is an explanatory diagram illustrating physical channels used in the LTE communication system.
  • a physical broadcast channel (Physical401Broadcast channel: PBCH) 401 is a channel for downlink transmission from the base station 102 to the mobile terminal 101.
  • a BCH transport block (transport block) is mapped to four subframes in a 40 ms interval. There is no obvious signaling of 40ms timing.
  • a physical control channel format indicator channel (Physical Control Format Indicator Indicator Channel: PCFICH) 402 is a channel for downlink transmission from the base station 102 to the mobile terminal 101.
  • PCFICH notifies base station 102 to mobile terminal 101 about the number of OFDM symbols used for PDCCHs.
  • PCFICH is transmitted for each subframe.
  • a physical downlink control channel (Physical Downlink Control Channel: PDCCH) 403 is a channel for downlink transmission from the base station 102 to the mobile terminal 101.
  • the PDCCH includes resource allocation, HARQ (HybridbrRepeat reQuest) information on DL-SCH (a downlink shared channel which is one of the transport channels shown in FIG. 5 described later), PCH (transformer shown in FIG. 5).
  • a paging channel which is one of the port channels).
  • the PDCCH carries an uplink scheduling grant (Uplink Scheduling Grant).
  • the PDCCH carries Ack (Acknowledgement) / Nack (Negative Acknowledgment) which is a response signal for uplink transmission.
  • the PDCCH is also called an L1 / L2 control signal.
  • a physical downlink shared channel (PDSCH) 404 is a channel for downlink transmission from the base station 102 to the mobile terminal 101.
  • DL-SCH (downlink shared channel) that is a transport channel and PCH that is a transport channel are mapped to the PDSCH.
  • a physical multicast channel (PMCH) 405 is a channel for downlink transmission from the base station 102 to the mobile terminal 101.
  • a multicast channel (Multicast Channel: MCH) that is a transport channel is mapped to the PMCH.
  • a physical uplink control channel (Physical Uplink Control Channel: PUCCH) 406 is a channel for uplink transmission from the mobile terminal 101 to the base station 102.
  • the PUCCH carries Ack / Nack which is a response signal (response) to downlink transmission.
  • the PUCCH carries a CQI (Channel Quality Indicator) report.
  • CQI is quality information indicating the quality of received data or channel quality.
  • the PUCCH carries a scheduling request (SR).
  • a physical uplink shared channel (Physical-Uplink-Shared-Channel: PUSCH) 407 is a channel for uplink transmission from the mobile terminal 101 to the base station 102.
  • UL-SCH uplink shared channel which is one of the transport channels shown in FIG. 5 is mapped to PUSCH.
  • the physical HARQ indicator channel (Physical Hybrid ARQ Indicator Channel: PHICH) 408 is a channel for downlink transmission from the base station 102 to the mobile terminal 101.
  • PHICH carries Ack / Nack which is a response to uplink transmission.
  • a physical random access channel (Physical Random Access Channel: PRACH) 409 is a channel for uplink transmission from the mobile terminal 101 to the base station 102.
  • the PRACH carries a random access preamble.
  • Downlink reference signal is a symbol known as a mobile communication system.
  • the downlink reference signal is inserted into the first, third and last OFDM symbols of each slot.
  • RSRP reference symbol received power
  • FIG. 5 is an explanatory diagram for explaining a transport channel used in an LTE communication system.
  • FIG. 5A shows the mapping between the downlink transport channel and the downlink physical channel.
  • FIG. 5B shows mapping between the uplink transport channel and the uplink physical channel.
  • BCH Broadcast Channel
  • PBCH physical broadcast channel
  • HARQ Hybrid ARQ
  • the DL-SCH can be broadcast to the entire coverage of the base station (cell).
  • DL-SCH supports dynamic or semi-static resource allocation. Quasi-static resource allocation is also referred to as persistent scheduling.
  • DL-SCH supports DRX (Discontinuous reception) of a mobile terminal in order to reduce power consumption of the mobile terminal.
  • the DL-SCH is mapped to the physical downlink shared channel (PDSCH).
  • the Paging Channel supports DRX of the mobile terminal in order to enable low power consumption of the mobile terminal.
  • the PCH is required to be broadcast to the entire coverage of the base station (cell).
  • the PCH is mapped to a physical resource such as a physical downlink shared channel (PDSCH) that can be dynamically used for traffic, or a physical resource such as a physical downlink control channel (PDCCH) of another control channel.
  • the multicast channel (Multicast Channel: MCH) is used for broadcast to the entire coverage of the base station (cell).
  • the MCH supports SFN combining of MBMS services (MTCH and MCCH) in multi-cell transmission.
  • the MCH supports quasi-static resource allocation.
  • MCH is mapped to PMCH.
  • Retransmission control by HARQ is applied to the uplink shared channel (Uplink Shared Channel: UL-SCH).
  • UL-SCH supports dynamic or semi-static resource allocation.
  • UL-SCH is mapped to a physical uplink shared channel (PUSCH).
  • the random access channel (Random Access Channel: RACH) shown in FIG. 5B is limited to control information.
  • RACH is at risk of collision.
  • the RACH is mapped to a physical random access channel (PRACH).
  • HARQ is a technique for improving the communication quality of a transmission path by a combination of automatic retransmission request (Automatic Repeat reQuest: ARQ) and error correction (Forward Error Correction).
  • ARQ Automatic Repeat reQuest
  • error correction Forward Error Correction
  • HARQ has an advantage that error correction functions effectively by retransmission even for a transmission path whose communication quality changes. In particular, further quality improvement can be obtained by combining the initial transmission reception result and the retransmission reception result upon retransmission.
  • Chase combining is a method of transmitting the same data in initial transmission and retransmission, and is a method of improving gain by combining initial transmission data and retransmission data in retransmission. This means that even if there is an error in the initial transmission data, the data is partially accurate, and the data is transmitted with higher accuracy by combining the correct initial transmission data and the retransmission data. It is based on the idea that it can be done.
  • Another example of the HARQ method is IR (Incremental Redundancy). IR is to increase redundancy, and by transmitting parity bits in retransmission, the redundancy is increased in combination with initial transmission, and the quality is improved by an error correction function.
  • FIG. 6 is an explanatory diagram illustrating logical channels used in the LTE communication system.
  • FIG. 6A shows mapping between the downlink logical channel and the downlink transport channel.
  • FIG. 6B shows mapping between the uplink logical channel and the uplink transport channel.
  • the broadcast control channel (Broadcast Control Channel: BCCH) is a downlink channel for broadcast system control information.
  • BCCH Broadcast Control Channel
  • the BCCH that is a logical channel is mapped to a broadcast channel (BCH) that is a transport channel or a downlink shared channel (DL-SCH).
  • BCH broadcast channel
  • DL-SCH downlink shared channel
  • the paging control channel is a downlink channel for transmitting a paging signal.
  • PCCH is used when the network does not know the cell location of the mobile terminal.
  • the PCCH that is a logical channel is mapped to a paging channel (PCH) that is a transport channel.
  • the common control channel (Common Control Channel: CCCH) is a channel for transmission control information between the mobile terminal and the base station.
  • CCCH is used when the mobile terminal does not have an RRC connection with the network.
  • the CCCH is mapped to a downlink shared channel (DL-SCH) that is a transport channel.
  • DL-SCH downlink shared channel
  • UL-SCH uplink shared channel
  • the multicast control channel (Multicast Control Channel: MCCH) is a downlink channel for one-to-many transmission.
  • the MCCH is used for transmission of MBMS control information for one or several MTCHs from the network to the mobile terminal.
  • MCCH is used only for mobile terminals that are receiving MBMS.
  • the MCCH is mapped to the downlink shared channel (DL-SCH) or multicast channel (MCH) which is a transport channel.
  • DL-SCH downlink shared channel
  • MCH multicast channel
  • the dedicated control channel (Dedicated Control Channel: DCCH) is a channel for transmitting dedicated control information between the mobile terminal and the network.
  • the DCCH is mapped to the uplink shared channel (UL-SCH) in the uplink, and is mapped to the downlink shared channel (DL-SCH) in the downlink.
  • the dedicated traffic channel (Dedicated Traffic Channel: DTCH) is a channel for one-to-one communication to individual mobile terminals for transmitting user information.
  • DTCH exists for both uplink and downlink.
  • the DTCH is mapped to the uplink shared channel (UL-SCH) in the uplink, and is mapped to the downlink shared channel (DL-SCH) in the downlink.
  • UL-SCH uplink shared channel
  • DL-SCH downlink shared channel
  • the multicast traffic channel is a downlink channel for transmitting traffic data from the network to the mobile terminal.
  • MTCH is a channel used only for a mobile terminal that is receiving MBMS.
  • the MTCH is mapped to a downlink shared channel (DL-SCH) or a multicast channel (MCH).
  • DL-SCH downlink shared channel
  • MCH multicast channel
  • GCI is a global cell identifier (Global Cell Identity).
  • CSG cells Cell
  • the CSG cell will be described below (see Non-Patent Document 3, Chapter 3.1).
  • the CSG (Closed Subscriber ⁇ ⁇ Group) cell is a cell in which an operator identifies an available subscriber (hereinafter referred to as a “cell for specific subscriber”). It may be said).
  • the identified subscribers are allowed to access one or more E-UTRAN cells of the PLMN (Public Land Mobile Mobile Network).
  • PLMN Public Land Mobile Mobile Network
  • One or more E-UTRAN cells to which the identified subscribers are allowed access are referred to as “CSG cells (CSG cell (s))”.
  • PLMN Public Land Mobile Mobile Network
  • the CSG cell is a part of the PLMN that broadcasts a unique CSG identity (CSG identity: CSG ID; CSG-ID). Members of the subscriber group who have been registered in advance and permitted access the CSG cell using the CSG-ID as access permission information.
  • CSG identity CSG ID; CSG-ID.
  • the CSG-ID is broadcast by the CSG cell or cell. There are a plurality of CSG-IDs in a mobile communication system. The CSG-ID is then used by the mobile terminal (UE) to facilitate access of CSG related members.
  • the location tracking of a mobile terminal is performed in units of areas composed of one or more cells. The position tracking is to enable tracking of the position of the mobile terminal and calling (the mobile terminal receives a call) even in the standby state. This area for tracking the location of the mobile terminal is called a tracking area.
  • the CSG white list (CSG white list) is a list stored in a USIM (Universal Subscriber Identity Module) in which all CSG IDs of CSG cells to which the subscriber belongs are recorded. The CSG white list may be referred to as an allowed CSG list (Allowed CSG ID List).
  • Suitable cell will be described below (see Non-Patent Document 3, Chapter 4.3).
  • a “suitable cell” is a cell that the UE camps on to receive normal service. Such a cell shall satisfy the following conditions:
  • the cell is a selected PLMN or a registered PLMN, or a part of the PLMN in the “Equivalent PLMN list”.
  • the latest information provided by NAS must satisfy the following conditions.
  • A The cell is not a barred cell.
  • B Be part of at least one tracking area (TA), not part of the “Forbidden LAs” list. In that case, the cell needs to satisfy the above (1).
  • C The cell satisfies the cell selection evaluation criteria.
  • D The cell is a CSG cell according to system information (SI). For the identified cell, the CSG-ID shall be part of the UE's “CSG WhiteList” (included in the UE's CSG WhiteList).
  • “Acceptable cell” will be described below (see Non-Patent Document 3, Chapter 4.3). This is a cell where the UE camps on in order to receive a limited service (emergency call). Such a cell shall satisfy all the following requirements: That is, the minimum set of requirements for initiating an emergency call in an E-UTRAN network is shown below. (1) The cell is not a barred cell. (2) The cell satisfies the cell selection evaluation criteria.
  • “Cam camp on cell” means that the UE has completed the cell selection (cell selection) or cell reselection (cell re-selection) process, and the UE monitors the system information and paging information. Selected state.
  • Non-Patent Document 4 discloses three different modes of access to HeNB and HNB. Specifically, an open access mode (Open access mode), a closed access mode (Closed access mode), and a hybrid access mode (Hybrid access mode).
  • Open access mode Open access mode
  • closed access mode closed access mode
  • Hybrid access mode Hybrid access mode
  • Each mode has the following characteristics.
  • the HeNB or HNB In the open access mode, the HeNB or HNB is operated as a normal cell of a normal operator.
  • the closed access mode the HeNB or HNB is operated as a CSG cell. This is a CSG cell accessible only to CSG members.
  • a non-CSG member In the hybrid access mode, a non-CSG member is a CSG cell to which access is permitted at the same time.
  • a cell in hybrid access mode (also referred to as a hybrid cell) is a cell that supports both an open access mode and a closed access mode.
  • Non-Patent Document 5 discloses a basic operation of a mobile terminal using PCI split.
  • a mobile terminal that does not have PCI split information needs to perform cell search using all PCIs, for example, using all 504 codes.
  • a mobile terminal having PCI split information can perform a cell search using the PCI split information.
  • LTE-A Long Term Evolution Advanced
  • relay relay node
  • the relay node is wirelessly connected to the radio access network via a donor cell (Donor cell; Donor eNB; DeNB).
  • Donor cell Donor cell; Donor eNB; DeNB
  • the network (NW) to relay link shares the same frequency band as the network to UE link.
  • a Release 8 UE can also be connected to the donor cell.
  • a link between the donor cell and the relay node is referred to as a backhaul link, and a link between the relay node and the UE is referred to as an access link.
  • transmission from DeNB to RN is performed in a downlink (DL) frequency band
  • transmission from RN to DeNB is performed in an uplink (UL) frequency band.
  • DL downlink
  • UL uplink
  • a link from DeNB to RN and a link from RN to UE are time-division multiplexed in one frequency band
  • a link from RN to DeNB and a link from UE to RN are also one frequency band. Is time-division multiplexed. By doing so, it is possible to prevent the relay transmission from interfering with the reception of the own relay in the relay.
  • Heterogeneous networks was added as one of the technologies to be studied in LTE-A.
  • low output power local area range network nodes such as pico eNBs (pico cells), hot zone cell nodes, HeNB / HNB / CSG cells, relay nodes, remote radio heads (RRH) It has been decided to handle.
  • Non-Patent Document 8 discloses a technique for realizing reduction of power consumption of infrastructure.
  • the eNB shifts to a transmission state called extended cell (DiscontinuousDisTransmission: DTX). Can do.
  • the eNB transmits only a reference signal RS (Reference Signal) necessary for demodulation of SS, PBCH, and PBCH.
  • RS Reference Signal
  • the transmission state for the UE in the standby (RRC_IDLE or IDLE) state is not clearly defined.
  • the UE In the standby state, the UE only needs to receive information related to paging in the DRX cycle according to the standard.
  • SS and PBCH transmitted in the extended cell DTX are signals that need not be received by the UE in the standby state. Since the extension cell DTX is transmitted unnecessary for the UE in the standby state, there is a problem that low power consumption cannot be efficiently realized.
  • An object of the present invention is to provide a mobile communication system that can efficiently reduce power consumption in a network node even when a mobile terminal device (UE) in a standby state exists.
  • UE mobile terminal device
  • the mobile communication system of the present invention is a mobile communication system comprising a base station device and a mobile terminal device capable of wireless communication with the base station device, wherein the mobile terminal device is in a state in which power is turned on.
  • a call signal for calling the mobile terminal device transmitted from the base station device is intermittently received, and the base station device is configured so that the mobile terminal device is in the standby state.
  • the reference signals for obtaining the reception level in the mobile terminal apparatus of the call signal and the signal transmitted from the base station apparatus in a call period periodically determined in advance as a period for transmitting the call signal. At least an intermittent transmission operation for transmitting the reference signal is performed.
  • the base station device when the mobile terminal device is in a standby state, the base station device performs an intermittent transmission operation for transmitting at least the reference signal among the calling signal and the reference signal during the calling period.
  • the mobile terminal apparatus can receive the reference signal during the paging period, so that the reception level of the signal transmitted from the base station apparatus can be obtained and used for determining the presence or absence of the paging signal.
  • the base station apparatus can suppress transmission power during periods other than the calling period, power consumption can be reduced. Therefore, even when there is a mobile terminal apparatus in a standby state, it is possible to efficiently reduce power consumption in the base station apparatus that is a network node.
  • FIG. 2 is an explanatory diagram showing a configuration of a radio frame used in an LTE communication system. It is explanatory drawing which shows the structure of a MBSFN frame. It is explanatory drawing explaining the physical channel used with the communication system of a LTE system. It is explanatory drawing explaining the transport channel used with the communication system of a LTE system. It is explanatory drawing explaining the logical channel used with the communication system of a LTE system. It is a block diagram which shows the whole structure of the mobile communication system of the LTE system currently discussed in 3GPP. It is a block diagram which shows the structure of the mobile terminal (mobile terminal 71 of FIG. 7) which concerns on this invention.
  • FIG. 7 It is a block diagram which shows the structure of the base station (base station 72 of FIG. 7) based on this invention. It is a block diagram which shows the structure of MME which concerns on this invention (MME part 73 of FIG. 7). It is a block diagram which shows the structure of HeNBGW74 shown in FIG. 7 which is HeNBGW which concerns on this invention.
  • 5 is a flowchart illustrating an outline from a cell search to a standby operation performed by a mobile terminal (UE) in an LTE communication system.
  • 10 is a timing chart illustrating the problem of Non-Patent Document 8. It is a location figure explaining the subject of nonpatent literature 8.
  • 6 is a timing chart for explaining an example of a base station transmission signal using the solution of the first embodiment.
  • FIG. 3 is a location diagram illustrating a solution of the first embodiment.
  • FIG. 3 is a state transition diagram illustrating a solution of the first embodiment.
  • FIG. 3 is a state transition diagram illustrating a solution of the first embodiment. It is a figure explaining the example of a sequence of the mobile communication system at the time of using the solution of Embodiment 1.
  • FIG. It is a figure explaining the example of a sequence of the mobile communication system at the time of using the solution of Embodiment 1.
  • FIG. It is a figure explaining the example of a sequence of the mobile communication system at the time of using the solution of Embodiment 1.
  • FIG. It is a figure explaining the example of a sequence of the mobile communication system at the time of using the solution of Embodiment 1.
  • FIG. It is a figure explaining the example of a sequence of the mobile communication system at the time of using the solution of Embodiment 1.
  • FIG. It is a figure explaining the example of a sequence of the mobile communication system at the time of using the solution
  • FIG. 10 is a location diagram illustrating a problem of the first modification of the first embodiment. 10 is a location diagram illustrating a solution of the first modification of the first embodiment.
  • FIG. 10 is a figure explaining the example of a sequence of the mobile communication system at the time of using the solution of the modification 1 of Embodiment 1.
  • FIG. It is a figure explaining the example of a sequence of the mobile communication system at the time of using the solution of the modification 1 of Embodiment 1.
  • FIG. 10 is a figure explaining the example of a sequence of the mobile communication system at the time of using the solution of the modification 1 of Embodiment 1.
  • FIG. 10 is a figure explaining the example of a sequence of the mobile communication system at the time of using the solution of the modification 1 of Embodiment 1.
  • FIG. 10 is a timing chart illustrating an example of a base station transmission signal using the solution of the first modification of the first embodiment.
  • FIG. 10 is a location diagram illustrating a problem of the second modification of the first embodiment.
  • 10 is a timing chart illustrating an example of a base station transmission signal using the solution of the second modification of the first embodiment. It is a state transition diagram explaining the solution of the modification 2 of Embodiment 1.
  • FIG. FIG. 10 is a timing chart illustrating an example of a base station transmission signal using the solution of the first modification of the first embodiment.
  • FIG. 11 is a location diagram for explaining a solution of the second modification of the first embodiment.
  • FIG. 10 is a location diagram for explaining a problem of the third modification of the first embodiment. It is a figure explaining the example of a sequence of the mobile communication system at the time of using the solution of the modification 3 of Embodiment 1.
  • FIG. It is a figure explaining the example of a sequence of the mobile communication system at the time of using the solution of the modification 3 of Embodiment 1.
  • FIG. It is a figure explaining the example of a sequence of the mobile communication system at the time of using the solution of the modification 3 of Embodiment 1.
  • FIG. 10 is a location diagram for explaining a problem of the third modification of the first embodiment. It is a figure explaining the example of a sequence of the mobile communication system at the time of using the solution of the modification 3 of Embodiment 1.
  • FIG. It is a figure explaining the example of a sequence of the mobile communication system at the time of using the solution of the modification 3 of Embodiment 1.
  • FIG. 7 is a block diagram showing the overall configuration of an LTE mobile communication system currently under discussion in 3GPP.
  • CSG Cell Subscriber Group
  • E-UTRAN Home-eNodeB Home-eNodeB
  • HeNB HeNB
  • UTRAN Home-NB HNB
  • non-CSG cells E-UTRAN eNodeB
  • eNB UTRAN NodeB
  • GERAN BSS GERAN BSS
  • a mobile terminal device (hereinafter referred to as “user terminal (UE)”) 71 is capable of wireless communication with a base station device (hereinafter referred to as “base station”) 72 and transmits and receives signals by wireless communication.
  • the base station 72 is classified into an eNB 72-1 and a Home-eNB 72-2.
  • the eNB 72-1 is connected to the MME, S-GW, or the MME / S-GW unit (hereinafter referred to as “MME unit”) 73 including the MME and the S-GW via the S1 interface. Control information is communicated between the two.
  • a plurality of MME units 73 may be connected to one eNB 72-1.
  • the eNBs 72-1 are connected by the X2 interface, and control information is communicated between the eNBs 72-1.
  • the Home-eNB 72-2 is connected to the MME unit 73 via the S1 interface, and control information is communicated between the Home-eNB 72-2 and the MME unit 73.
  • a plurality of Home-eNBs 72-2 are connected to one MME unit 73.
  • the Home-eNB 72-2 is connected to the MME unit 73 via a HeNBGW (Home-eNB GateWay) 74.
  • Home-eNB 72-2 and HeNBGW 74 are connected via an S1 interface, and HeNBGW 74 and MME unit 73 are connected via an S1 interface.
  • One or a plurality of Home-eNBs 72-2 are connected to one HeNBGW 74, and information is communicated through the S1 interface.
  • the HeNBGW 74 is connected to one or a plurality of MME units 73, and information is communicated through the S1 interface.
  • the X2 interface between Home-eNB 72-2 is not supported. From the MME unit 73, the HeNBGW 74 appears as an eNB 72-1. From the Home-eNB 72-2, the HeNBGW 74 appears as the MME unit 73. Regardless of whether or not the Home-eNB 72-2 is connected to the MME unit 73 via the HeNBGW 74, the interface between the Home-eNB 72-2 and the MME unit 73 is the same in the S1 interface. The HeNBGW 74 does not support mobility to the Home-eNB 72-2 or mobility from the Home-eNB 72-2 that spans a plurality of MME units 73. Home-eNB 72-2 supports only one cell.
  • FIG. 8 is a block diagram showing a configuration of a mobile terminal (mobile terminal 71 in FIG. 7) according to the present invention.
  • a transmission process of the mobile terminal 71 shown in FIG. 8 will be described.
  • control data from the protocol processing unit 801 and user data from the application unit 802 are stored in the transmission data buffer unit 803.
  • the data stored in the transmission data buffer unit 803 is transferred to the encoder unit 804 and subjected to encoding processing such as error correction.
  • the data encoded by the encoder unit 804 is modulated by the modulation unit 805.
  • the modulated data is converted into a baseband signal, and then output to the frequency conversion unit 806, where it is converted into a radio transmission frequency.
  • a transmission signal is transmitted from the antenna 807 to the base station 72.
  • the reception process of the mobile terminal 71 is executed as follows.
  • a radio signal from the base station 72 is received by the antenna 807.
  • the reception signal is converted from a radio reception frequency to a baseband signal by the frequency conversion unit 806, and demodulated by the demodulation unit 808.
  • the demodulated data is passed to the decoder unit 809 and subjected to decoding processing such as error correction.
  • control data is passed to the protocol processing unit 801, and user data is passed to the application unit 802.
  • a series of processing of the mobile terminal 71 is controlled by the control unit 810. Therefore, the control unit 810 is connected to the respective units 801 to 809, which is omitted in FIG.
  • FIG. 9 is a block diagram showing the configuration of the base station (base station 72 in FIG. 7) according to the present invention.
  • the base station 72 includes an EPC communication unit 901, another base station communication unit 902, a protocol communication unit 903, a transmission data buffer unit 904, an encoder unit 905, a modulation unit 906, a frequency conversion unit 907, an antenna 908, a demodulation unit 909, and a decoder unit.
  • 910, the control part 1211, and the cell (Cell) DTX control part 915 are comprised.
  • the EPC communication unit 901 transmits and receives data between the base station 72 and the EPC (including the MME unit 73, the HeNBGW 74, and the like) that is a core network.
  • a device constituting the core network such as the MME and the HeNBGW corresponds to a network control device.
  • the other base station communication unit 902 transmits / receives data to / from other base stations.
  • the eNB 72-1 and the Home-eNB 72-2 shown in FIG. 7 as the base station 72 the X2 interface between the Home-eNB 72-2 is not supported. It is also conceivable that the communication unit 902 does not exist.
  • the EPC communication unit 901 and the other base station communication unit 902 exchange information with the protocol processing unit 903, respectively.
  • control data from the protocol processing unit 903 and user data and control data from the EPC communication unit 901 and the other base station communication unit 902 are stored in the transmission data buffer unit 904.
  • Data stored in the transmission data buffer unit 904 is transferred to the encoder unit 905 and subjected to encoding processing such as error correction.
  • encoding processing such as error correction.
  • the encoded data is subjected to modulation processing by the modulation unit 906.
  • the modulated data is converted into a baseband signal, and then output to the frequency conversion unit 907 to be converted into a radio transmission frequency. Thereafter, a transmission signal is transmitted from the antenna 908 to one or a plurality of mobile terminals 71.
  • the cell DTX control unit 915 includes a UE state monitoring unit 912, a transmission state determination unit 913, and a transmission ON / OFF control unit 914.
  • the UE state monitoring unit 912 monitors the state of the UE based on information on the UE given from the protocol processing unit 903 and notifies the transmission state determination unit 913 of the UE. Although different from the present embodiment, in the technique disclosed in Non-Patent Document 8 described above, the UE state monitoring unit 912 monitors whether there is an active UE within the coverage of the base station 72, and the UE Is notified to the transmission state determination unit 913.
  • the transmission state determination unit 913 determines what state the transmission state of the base station 72 is to be based on based on the UE state given from the UE state monitoring unit 912. In other words, the transmission state determination unit 913 determines a state to be set as the transmission state of the base station 72.
  • the transmission state determination unit 913 is notified from the UE state monitoring unit 912 that there is no active UE, it is expanded.
  • the transmission state determination unit 913 notifies the transmission ON / OFF control unit 914 of the determination result.
  • the transmission ON / OFF control unit 914 controls the frequency conversion unit 907 to turn on (ON) the transmission operation at the timing when there is a signal to be transmitted, that is, to perform the transmission operation, and to transmit a signal ( Hereinafter, at a timing when there is no “downlink transmission signal”, the transmission operation is turned off, that is, the transmission operation is controlled not to be performed.
  • the transmission ON / OFF control unit 914 provides a transmission ON / OFF control signal to the frequency conversion unit 907 according to the determination result notified from the transmission state determination unit 913.
  • the reception process of the base station 72 is executed as follows. Radio signals from one or a plurality of mobile terminals 71 are received by the antenna 908. The reception signal is converted from a radio reception frequency to a baseband signal by the frequency conversion unit 907, and demodulated by the demodulation unit 909. The demodulated data is transferred to the decoder unit 910 and subjected to decoding processing such as error correction. Of the decoded data, the control data is passed to the protocol processing unit 903 or the EPC communication unit 901 and the other base station communication unit 902, and the user data is passed to the EPC communication unit 901 and the other base station communication unit 902. A series of processing of the base station 72 is controlled by the control unit 911. Therefore, the control unit 911 is connected to the respective units 901 to 910 and 915 of the base station 72 although omitted in FIG.
  • the functions of Home-eNB 72-2 currently being discussed in 3GPP are shown below (see Non-Patent Document 1, Chapter 4.6.2).
  • the Home-eNB 72-2 has the same function as the eNB 72-1.
  • the Home-eNB 72-2 has a function of finding an appropriate serving HeNBGW 74.
  • the Home-eNB 72-2 is only connected to one HeNBGW 74. That is, in the case of connection with the HeNBGW 74, the Home-eNB 72-2 does not use the Flex function in the S1 interface.
  • the Home-eNB 72-2 is not simultaneously connected to another HeNBGW 74 or another MME unit 73.
  • the TAC and PLMN ID of the Home-eNB 72-2 are supported by the HeNBGW 74.
  • the selection of the MME unit 73 in “UE attachment” is performed by the HeNBGW 74 instead of the Home-eNB 72-2.
  • Home-eNB 72-2 may be deployed without network planning. In this case, Home-eNB 72-2 is moved from one geographic region to another. Therefore, the Home-eNB 72-2 in this case needs to be connected to different HeNBGW 74 depending on the position.
  • FIG. 10 is a block diagram showing the configuration of the MME (MME unit 73 in FIG. 7) according to the present invention.
  • the PDN GW communication unit 1001 transmits and receives data between the MME unit 73 and the PDN GW.
  • the base station communication unit 1002 performs data transmission / reception between the MME unit 73 and the base station 72 through the S1 interface. If the data received from the PDN GW is user data, the user data is passed from the PDN GW communication unit 1001 to the base station communication unit 1002 via the user plane communication unit 1003 to one or a plurality of base stations 72. Sent. When the data received from the base station 72 is user data, the user data is passed from the base station communication unit 1002 to the PDN GW communication unit 1001 via the user plane communication unit 1003 and transmitted to the PDN GW.
  • control data is passed from the PDN GW communication unit 1001 to the control plane control unit 1005.
  • control data is transferred from the base station communication unit 1002 to the control plane control unit 1005.
  • the HeNBGW communication unit 1004 is provided when the HeNBGW 74 exists, and transmits and receives data through an interface (IF) between the MME unit 73 and the HeNBGW 74 depending on the information type.
  • the control data received from the HeNBGW communication unit 1004 is passed from the HeNBGW communication unit 1004 to the control plane control unit 1005.
  • the result of processing in the control plane control unit 1005 is transmitted to the PDN GW via the PDN GW communication unit 1001. Further, the result processed by the control plane control unit 1005 is transmitted to one or a plurality of base stations 72 via the S1 interface via the base station communication unit 1002, and to one or a plurality of HeNBGWs 74 via the HeNBGW communication unit 1004. Sent.
  • the control plane control unit 1005 includes a NAS security unit 1005-1, an SAE bearer control unit 1005-2, an idle state mobility management unit 1005-3, and the like, and performs overall processing for the control plane.
  • the NAS security unit 1005-1 performs security of a NAS (Non-Access Stratum) message.
  • the SAE bearer control unit 1005-2 manages a bearer of SAE (System Architecture) Evolution.
  • the idle state mobility management unit 1005-3 manages mobility in a standby state (LTE-IDLE state, also simply referred to as idle), generation and control of a paging signal in the standby state, and one or more mobile terminals 71 being served thereby Add, delete, update, search, and track area list (TA ⁇ ⁇ ⁇ List) management.
  • the MME unit 73 initiates the paging protocol by transmitting a paging message to a cell belonging to a tracking area (tracking area: Tracking Area: TA) in which the UE is registered.
  • the idle state mobility management unit 1005-3 may perform CSG management, CSG-ID management, and white list management of the Home-eNB 72-2 connected to the MME unit 73.
  • the relationship between the mobile terminal corresponding to the CSG-ID and the CSG cell is managed (added, deleted, updated, searched). For example, it may be a relationship between one or a plurality of mobile terminals registered for user access with a certain CSG-ID and a CSG cell belonging to the CSG-ID.
  • white list management the relationship between a mobile terminal and a CSG-ID is managed (added, deleted, updated, searched). For example, one or a plurality of CSG-IDs registered by a certain mobile terminal as a user may be stored in the white list. Management related to these CSGs may be performed in other parts of the MME unit 73. A series of processing of the MME unit 73 is controlled by the control unit 1006. Therefore, although not shown in FIG. 10, the control unit 1006 is connected to the units 1001 to 1005.
  • the functions of MME currently being discussed in 3GPP are shown below (refer to Chapter 4.6.2 of Non-Patent Document 1).
  • the MME performs access control of one or a plurality of mobile terminals of CSG (Closed Subscriber Group).
  • CSG Cellular Subscriber Group
  • the MME accepts paging optimization as an option.
  • FIG. 11 is a block diagram showing a configuration of the HeNBGW 74 shown in FIG. 7 which is the HeNBGW according to the present invention.
  • the EPC communication unit 1101 performs data transmission / reception between the HeNBGW 74 and the MME unit 73 through the S1 interface.
  • the base station communication unit 1102 performs data transmission / reception between the HeNBGW 74 and the Home-eNB 72-2 via the S1 interface.
  • the location processing unit 1103 performs a process of transmitting registration information and the like among the data from the MME unit 73 delivered via the EPC communication unit 1101 to the plurality of Home-eNBs 72-2.
  • the data processed by the location processing unit 1103 is passed to the base station communication unit 1102 and transmitted to one or more Home-eNBs 72-2 via the S1 interface.
  • Data that does not require processing in the location processing unit 1103 and is simply passed (transmitted) is passed from the EPC communication unit 1101 to the base station communication unit 1102 and sent to one or more Home-eNBs 72-2 via the S1 interface. Sent.
  • a series of processing of the HeNBGW 74 is controlled by the control unit 1104. Therefore, although not shown in FIG. 11, the control unit 1104 is connected to the units 1101 to 1103.
  • HeNBGW74 The functions of HeNBGW74 currently being discussed in 3GPP are shown below (see Non-Patent Document 1, Chapter 4.6.2).
  • the HeNBGW 74 relays for the S1 application. Although part of the procedure of the MME unit 73 to the Home-eNB 72-2, the HeNBGW 74 terminates the S1 application not related to the mobile terminal 71.
  • the HeNBGW 74 When the HeNBGW 74 is arranged, procedures unrelated to the mobile terminal 71 are communicated between the Home-eNB 72-2 and the HeNBGW 74, and between the HeNBGW 74 and the MME unit 73.
  • the X2 interface is not set between the HeNBGW 74 and other nodes.
  • the HeNBGW 74 recognizes execution of paging optimization (Paging optimization) as an option.
  • Paging optimization paging optimization
  • FIG. 12 is a flowchart showing an outline from a cell search to a standby operation performed by a mobile terminal (UE) in an LTE communication system.
  • the mobile terminal uses the first synchronization signal (P-SS) and the second synchronization signal (S-SS) transmitted from the neighboring base stations in step ST1201, and the slot timing, frame Synchronize timing.
  • the synchronization signal (SS) is assigned a synchronization code corresponding to one-to-one PCI (Physical Cell Identity) assigned to each cell.
  • PCI Physical Cell Identity
  • a reference signal RS Reference signal
  • the reference signal RS uses a code corresponding to the PCI one-to-one, and can be separated from other cells by taking a correlation with the code.
  • step ST1203 the cell having the best RS reception quality, for example, the cell having the highest RS reception power, that is, the best cell is selected from one or more cells detected up to step ST1202.
  • the PBCH of the best cell is received and the BCCH that is broadcast information is obtained.
  • MIB Master Information Block
  • the MIB information includes, for example, DL (downlink) system bandwidth (also called transmission bandwidth setting (transmission bandwidth configuration: dl-bandwidth)), the number of transmission antennas, SFN (System frame number), and the like.
  • SIB1 System Information Block 1 in the broadcast information BCCH.
  • SIB1 includes information related to access to the cell, information related to cell selection, and scheduling information of other SIBs (SIBk; an integer of k ⁇ 2). Also, SIB1 includes TAC (Tracking Area Code).
  • step ST1206 the mobile terminal compares the TAC of SIB1 received in step ST1205 with the TAC already held by the mobile terminal. If the result of the comparison is the same, a standby operation is started in the cell. If they are different from each other, the mobile terminal requests a change of TA to perform TAU (Tracking Area Update) to the core network (Core-Network, EPC) (including MME) through the cell.
  • the core network updates the TA based on the identification number (UE-ID or the like) of the mobile terminal sent from the mobile terminal together with the TAU request signal. After updating the TA, the core network transmits a TAU receipt signal to the mobile terminal.
  • the mobile terminal rewrites (updates) the TAC (or TAC list) held by the mobile terminal with the TAC of the cell. Thereafter, the mobile terminal enters a standby operation in the cell.
  • CSG Cell Subscriber Group
  • access is permitted only to one or a plurality of mobile terminals registered in the CSG cell.
  • a CSG cell and one or more registered mobile terminals constitute one CSG.
  • a CSG configured in this way is given a unique identification number called CSG-ID.
  • a single CSG may have a plurality of CSG cells. If a mobile terminal registers in any one CSG cell, it can access another CSG cell to which the CSG cell belongs.
  • Home-eNB in LTE and Home-NB in UMTS may be used as CSG cells.
  • the mobile terminal registered in the CSG cell has a white list.
  • the white list is stored in SIM (Subscriber Identity Module) / USIM.
  • the white list stores CSG information of CSG cells registered by the mobile terminal.
  • CSG-ID, TAI (Tracking Area Identity), TAC, etc. can be considered as the CSG information.
  • Either of the CSG-ID and the TAC may be used as long as they are associated with each other.
  • GCI may be used as long as CSG-ID and TAC are associated with GCI (Global Cell Identity).
  • a mobile terminal that does not have a white list cannot access a CSG cell, and only accesses a non-CSG cell. Can not.
  • a mobile terminal having a white list can access both a CSG cell of a registered CSG-ID and a non-CSG cell.
  • Non-Patent Document 5 discloses a basic operation of a mobile terminal using PCI split.
  • a mobile terminal that does not have PCI split information needs to perform cell search using all PCIs, for example, using all 504 codes.
  • a mobile terminal having PCI split information can perform a cell search using the PCI split information.
  • PCI for hybrid cells is not included in the PCI range for CSG cells (see Non-Patent Document 1, Chapter 10.7).
  • the HeNB and HNB are required to support various services. For example, an operator increases a radio resource that can be used by a mobile terminal by allowing the mobile terminal to be registered in a certain HeNB and HNB and allowing only the registered mobile terminal to access the HeNB and HNB cells. To enable high-speed communication. Accordingly, the service is such that the operator sets the charging fee higher than usual.
  • CSG cell Cell
  • CSG cells Cell Subscriber Group ⁇ ⁇ ⁇ cell
  • a CSG cell is installed for each store in a shopping street, each room in a condominium, each classroom in a school, and each section in a company, and only a user registered in each CSG cell can use the CSG cell.
  • HeNB / HNB is required not only to complement communication outside the coverage of the macro cell, but also to support various services as described above. For this reason, a case where the HeNB / HNB is installed in the coverage of the macro cell may occur.
  • Heterogeneous networks was added as one of the technologies to be studied in LTE-A.
  • a low output power local area range such as a pico eNB (pico cell), a node for a hot zone cell, a HeNB / HNB / CSG cell, a relay node, a remote radio head (RRH) range) network nodes (local area range node (local area node), local area node (local area node), local node (local node)). Therefore, it is required to operate a network in which one or more such local area range nodes are incorporated in a normal eNB (macro cell).
  • a network in which one or more local area range nodes are incorporated in a normal eNB (macro cell) is called heterogeneous networks, and an interference reduction method, a capacity improvement method, and the like are studied.
  • the base station when there is no active UE in the coverage area of the cell formed by the base station, that is, in the coverage, or when the existing UE is in the IDLE mode (standby state), the base station Transmits only SS and PBCH. When there is no OFDM symbol to be transmitted, the base station can reduce power consumption by turning off transmission.
  • FIG. 13 is a timing chart for explaining the problem of Non-Patent Document 8.
  • the SS is arranged in the first subframe # 0 and the sixth subframe # 5 in the radio frame (10 ms), and the PBCH is 1 in the radio frame (10 ms).
  • Arranged in the first subframe # 0. Therefore, when there are SS symbols and PBCH OFDM symbols in a period of 5 ms, the base station turns on the transmission operation (ON) to transmit a downlink transmission signal to be transmitted to the UE, and turns off the transmission operation in other periods. (OFF) to stop the transmission operation of the downlink transmission signal.
  • This technique is called extended cell DTX (Discontinuous Transmission).
  • Non-Patent Document 8 even when the UE is in the IDLE mode (standby state), the base station transmits SS and PBCH in the extended cell DTX. On the other hand, when the UE is in a standby state, in order to reduce power consumption, the UE transmits only paging information and cells in a relatively long period called DRX (Discontinuous Reception) period, for example, a period of about 1 to 5 seconds. Receiving. Network nodes in the local area range target only limited UEs belonging to the CSG.
  • DRX discontinuous Reception
  • Non-Patent Document 8 does not mention that the IDLE mode UE receives paging in the DRX cycle.
  • the base station transmits paging information to the UE only when paging for the UE, i.e., when a call originates from the network.
  • the UE performs reception at the timing when the paging information is transmitted, and first determines the presence or absence of paging.
  • the timing at which paging information is transmitted is called PO (Paging (Occasion).
  • a network node in the local area range is referred to as a local eNB (Local eNB).
  • the local eNB has relatively small output power that is transmission power.
  • a wide area eNB for example, a normal eNB (macro cell) has a relatively large output power. That is, the output power of the local eNB is smaller than the output power of the wide area eNB.
  • the local eNB may be referred to as a local base station device.
  • FIG. 14 is a location diagram illustrating the problem of Non-Patent Document 8.
  • a mobile terminal (UE) 1403 exists in a coverage 1402 that is a communicable range of the local eNB 1401.
  • the UE 1403 is the only UE belonging to the CSG of the local eNB 1401. It is assumed that the mobile terminal 1403 is in a standby state (IDLE) and receives the PO of the local eNB 1401 with a DRX cycle, specifically, a cycle of about 1 to 5 seconds.
  • IDLE standby state
  • the local eNB 1401 transmits the UE 1403 in the coverage 1402 by applying the extended cell DTX because the UE 1403 in the coverage 1402 is IDLE, that is, transmits the SS and the PBCH at a cycle of 5 ms. Since the UE belonging to the CSG is only the UE 1403, there arises a problem that transmission of SS and PBCH that are not received by the UE 1403 is wasted.
  • Non-Patent Document 8 Another problem of the method disclosed in Non-Patent Document 8 is described below.
  • an implementation may be considered in which the presence or absence of paging is estimated by determining the threshold of the strength of the paging signal that is a call signal on the basis of the received signal strength of the RS.
  • the base station performing the extended cell DTX does not transmit even RS in PO when there is no paging. Therefore, the UE that receives the PO by the implementation means described above has a higher probability of erroneously determining the presence or absence of paging, and the useless operation time increases. This may cause a problem that the power consumption of the UE increases.
  • the solution in the first embodiment is shown below.
  • reduction of power consumption is supported by the local eNB.
  • a specific example of an implementation method for supporting reduction of power consumption is shown below.
  • a method is disclosed in which the ratio of transmission OFF is further increased compared to the extended cell DTX disclosed in Non-Patent Document 8 to reduce the power consumption of the local eNB.
  • FIG. 15 shows an operation example of the local eNB in the situation of FIG.
  • FIG. 15 is a timing chart for explaining an example of a base station transmission signal using the solution of the first embodiment.
  • UEs in the coverage of the local eNB that is, in the cell range, are in the IDLE mode, that is, in a standby state, and in a DRX cycle (about 1 to 5 seconds), a paging frame (Paging Frame 150: PO 1504 included in the radio frame of (PF) 1503 is received.
  • the local eNB transmits only PO 1504 at the timing when the transmission ON signal 1501 is transmitted.
  • the transmission eNB signal 1501 of the local eNB is turned on, that is, transmitted only during the period of the PO1504 subframe (about 1 ms) in the DRX cycle (about 1 to 5 seconds). Thereby, the ratio of the transmission time can be significantly reduced as compared with the extended cell DTX disclosed in Non-Patent Document 8.
  • the DRX cycle corresponds to the second transmission cycle.
  • the local eNB transmits the PDSCH and the accompanying PDCCH and RS in PO 1504.
  • the UE that receives the PO 1504 in the standby state can always receive the RS at the timing of the PO 1504, and thus can have an advantage in the following three performances.
  • the reception level RSRP of the local eNB can be monitored.
  • the UE also monitors RSRPs of other eNBs and local eNBs, and uses them for determination of cell reselection.
  • the frequency deviation between the received signal and the UE reference clock is estimated from the time variation of the channel estimation value.
  • the estimated frequency deviation value can be used for tracking of AFC (Automatic Frequency Control).
  • the presence or absence of a paging signal can be accurately determined using the received signal strength of the RS as a reference.
  • the transmission ON time in FIG. 15 may be a subframe period of PO 1504, a period in which PDCCH and PDSCH are transmitted in PO 1504, or a radio frame period of PF 1503.
  • RS or RS and PBCH are transmitted in a period when there is no PDCCH and PDSCH to be transmitted.
  • the above transmission ON time is defined as a calling period. That is, the calling period is, for example, a PO subframe period, a period in which there is PDCCH or PDSCH in the PO subframe period, or a PF radio frame period.
  • the local eNB when the UE is in a standby state, transmits at least a paging signal and an RS among the paging signal and the RS during a call period that is a period that is predetermined as a period for transmitting the paging signal.
  • An intermittent transmission operation for transmitting the RS is performed.
  • the reception level of the signal transmitted from the local eNB can be obtained using the RS, and can be used for determining the presence or absence of a paging signal.
  • local eNB can stop transmission operation
  • FIG. 16 is a location diagram for explaining the solution of the first embodiment. From FIG. 16 and FIG. 14 described above, the following three types of relations between the local eNB and the UE are conceivable.
  • the UE 1403 is in the coverage 1402 of the local eNB 1401 and is waiting in the IDLE mode.
  • the UE 1603 is covered by the local eNB 1601. State in 1602 and communicating in CONNECTED mode (3) State in which UE is out of coverage of local eNB (out of service area).
  • the relationship between the local eNB and the UE described above changes every moment depending on the movement of the UE and the service status, and there is a problem that the local eNB needs to change the transmission method according to the status.
  • a method for solving this problem will be disclosed below.
  • FIG. 17 is a state transition diagram for explaining the solution of the first embodiment.
  • FIG. 17 shows a transition diagram of transmission states determined by the transmission state determination unit 913 of the base station 72 shown in FIG.
  • the base station 72 which is the local eNB of the first embodiment, sets the transmission state to any one of the normal transmission 1701, the extended cell DTX 1702, and the DRX cycle cell DTX 1703 in the transmission state determination unit 913 shown in FIG. Judge whether to do. That is, in the transmission state determination unit 913, the base station 72 switches the transmission state to one of the normal transmission 1701, the extended cell DTX 1702, and the DRX cycle cell DTX 1703 as shown in FIG. In the state of normal transmission 1701, the local eNB performs normal transmission.
  • the local eNB transmits the extended cell DTX disclosed in Non-Patent Document 8.
  • the local eNB performs PO (RS, PDCCH, PDSCH) transmission with the DRX cycle disclosed in the first embodiment. In this way, the local eNB performs an intermittent transmission operation.
  • PO RS, PDCCH, PDSCH
  • FIG. 18 is a state transition diagram for explaining the solution of the first embodiment.
  • FIG. 18 shows a UE state transition diagram determined by the UE state monitoring unit 912 of the base station 72 shown in FIG. 9 described above.
  • the base station 72 which is the local eNB of the first embodiment, monitors the state of the UE registered in the CSG of the local eNB using the information from the protocol processing unit 903 in the UE state monitoring unit 912 illustrated in FIG. As shown in FIG. 18, it is determined which of the CONNECTED mode 1801, out of cell range, that is, out of coverage 1802, and IDLE mode 1803.
  • the local eNB determines the transmission state as follows in the transmission state determination unit 913 in FIG. 9 according to the state of the UE determined in the UE state monitoring unit 912 in FIG. 9.
  • a method of determining the UE state in the UE state monitoring unit 912 in the first embodiment will be disclosed below.
  • FIG. 19 is a diagram for explaining a sequence example of the mobile communication system when the solution of the first embodiment is used.
  • FIG. 19 shows a sequence from when the UE turns on the power, that is, after the power is turned on, until the UE enters a standby state in the cell of the local eNB. That is, FIG. 19 shows an example of the state transition indicated by the arrow 1804 in FIG.
  • Step ST1901 the UE selects an initial cell. For example, the UE selects a cell having the best reception quality. In this operation example, it is assumed that a local eNB is selected.
  • Step ST1902 the UE receives the system information of the local eNB selected in Step ST1901. As a result, the UE can know parameters for random access to the local eNB according to the contents of the system information (see 3GPP TS36.331 V9.1.0 (hereinafter referred to as “Non-patent Document 9”)).
  • Step ST1903 the UE performs PRACH transmission to the local eNB. Since the system information acquired in step ST1902 includes the CSG-ID of the local eNB (Non-Patent Document 9), in step ST1903, the UE has the CSG-ID of the selected local eNB in the white list in the UE. In this case, PRACH transmission may be performed.
  • the local eNB When receiving the PRACH transmitted from the UE, the local eNB starts normal transmission in Step ST1904. Moreover, if UE performs PRACH transmission by step ST1903 as mentioned above, it will become CONNECTED mode in step ST1905.
  • Step ST1906 and Step ST1907 the local eNB and the UE set up dedicated channel lines. Specifically, first, in step ST1906, the local eNB transmits a radio bearer setup message instructing the setting of the dedicated channel line to the UE. When receiving the radio bearer setup message transmitted from the local eNB, the UE performs a process of setting an individual channel line in step ST1907, and transmits a radio bearer setup complete (Radio Bearer Setup Complete) message to the local eNB. Therefore, the local eNB starts normal transmission in step ST1904 in order to start communication of the dedicated channel with the UE before the process of step ST1906. In Step ST1905, the UE enters a CONNECTED mode (also referred to as an RRC_CONNECTED mode).
  • a CONNECTED mode also referred to as an RRC_CONNECTED mode
  • Step ST1906 and Step ST1907 the UE transmits an Attach request (Attach Request) to the MME or HeNBGW through the local eNB in Step ST1908.
  • the MME or the HeNBGW notifies the UE of Attach approval (Attach Accept) through the local eNB.
  • the UE that has received the Attach acknowledgment notifies the MME of Attach completion (Attach Complete) through the local eNB.
  • Attach succeeds (see 3GPP TS 23.401 V9.4.0 (hereinafter referred to as “Non-Patent Document 10”)).
  • step ST1911 and step ST1912 the local eNB and UE release the dedicated channel line. Specifically, in step ST1911, the local eNB transmits a radio bearer release (RadioUEBearer Release) message to the UE.
  • the UE When receiving the radio bearer release message transmitted from the local eNB, the UE performs a process of releasing the dedicated channel line in step ST1912, and transmits a radio bearer release complete (Radio Bearer Release Complete) message to the local eNB.
  • Radio bearer release Radio Bearer Release
  • the local eNB When the local eNB receives the radio bearer release complete message transmitted from the UE, in step ST1913, the local eNB starts a cell DTX with a DRX cycle. Further, when the UE transmits a radio bearer release complete message in step ST1912, as described above, in step ST1914, the UE enters an IDLE mode and waits in a local eNB cell.
  • FIG. 20 is a diagram illustrating a sequence example of the mobile communication system when the solution of the first embodiment is used.
  • FIG. 20 shows a sequence from when the UE selects a local eNB by cell reselection to a standby state in the cell of the local eNB. That is, FIG. 20 shows an example of the state transition indicated by the arrow 1804 in FIG.
  • Step ST2001 the UE performs cell reselection. For example, the UE selects a cell with the best reception quality. In this operation example, it is assumed that a local eNB is selected.
  • Step ST2002 the local eNB transmits broadcast information to the UE.
  • the UE receives the system information of the local eNB selected in step ST2001.
  • the UE can know the parameter for random access to the local eNB, the tracking area code (TAC), and the CSG-ID of the local eNB according to the contents of the system information.
  • TAC tracking area code
  • TAU is performed when the UE enters a new tracking area that is not in the registered TAI (Tracking Area Identity) list (see Non-Patent Document 10).
  • TAI Tracking Area Identity
  • the UE does not perform TAU. Therefore, the problem that local eNB cannot detect that UE moved to the cell area from the cell area outside or the cell of another eNB occurs.
  • the UE that has received the system information in Step ST2002 determines whether or not the cell selected in Step ST2021 (hereinafter may be referred to as “selected cell”) is a local eNB. If it is eNB, it will transfer to step ST2003 and will perform TAU irrespective of the tracking area of this local eNB. By this process, the local eNB can detect that the UE has moved out of the cell area or from the cell of another eNB to the cell area. If the UE determines in step ST2021 that the selected cell is not a local eNB, the UE moves to step ST2022. In Step ST2022, the UE determines whether or not the TA is included in the TAI list (list). If the TA is not included, the UE moves to Step ST2003, and if included, the process ends.
  • the cell selected in Step ST2021 hereinafter may be referred to as “selected cell”
  • An indicator indicating whether or not the selected cell is a local eNB is newly provided in the system information.
  • the indicator included in the system information indicates that the selected cell is a local eNB
  • the UE determines that the selected cell is a local eNB, and the indicator indicates that the selected cell is a local eNB. If not, the UE determines that the selected cell is not a local eNB.
  • TAU may be performed regardless of the tracking area of the local eNB.
  • CSG-ID included in system information For example, if the CSG-ID is included, the UE determines that the selected cell is a HeNB, and if the CSG-ID is not included, the UE determines that the selected cell is not a HeNB.
  • csg-Indication included in system information. For example, if csg-Indication is “TRUE”, the UE determines that the selected cell is HeNB, and if csg-Indication is not “TRUE”, the UE determines that the selected cell is not HeNB.
  • hnb-Name included in system information. For example, if the hnb-Name is included, the UE determines that the selected cell is a HeNB. If the hnb-Name is not included, the UE determines that the selected cell is not a HeNB.
  • step ST2003 the UE performs PRACH transmission to the local eNB. Since the system information received in step ST2002 described above includes the CSG-ID of the local eNB, the UE transmits a PRACH in step ST2003 when the selected local eNB CSG-ID exists in the white list in the UE. May be performed.
  • the local eNB determines that the PRACH is from a UE belonging to the CSG, the local eNB permits access and sets an individual channel line through the processing of Step ST2006 and Step ST2007. Specifically, first, in step ST2006, the local eNB transmits a radio bearer setup message instructing the setting of the dedicated channel line to the UE. When receiving the radio bearer setup message transmitted from the local eNB, the UE performs a process of setting an individual channel line in step ST2007, and transmits a radio bearer setup complete message to the local eNB.
  • Step ST2004 the local eNB starts normal transmission in step ST2004 in order to start communication of the dedicated channel with the UE before the process of step ST2006.
  • Step ST2005 the UE enters a CONNECTED mode (also referred to as RRC_CONNECTED).
  • the UE executes TA Update (TAU) to the MME or HeNBGW through the local eNB in step ST2008.
  • TAU TA Update
  • the MME or the HeNBGW that has received TA Update in Step ST2008 transmits TA Update Accept to the UE through the local eNB.
  • Step ST2010 the UE that has received TA Update Accept in Step ST2009 transmits TA Update Complete to the MME or HeNBGW through the local eNB. This makes TAU successful.
  • step ST2011 the local eNB and the UE release the dedicated channel line.
  • the local eNB transmits a radio bearer release message to the UE.
  • the UE performs a process of releasing the dedicated channel line in step ST2012, and transmits the radio bearer release complete message to the local eNB.
  • the processes in steps ST2003 to ST2012 described above are referred to as a “TA Update sequence”.
  • the local eNB starts a cell DTX with a DRX cycle in step ST2013.
  • the UE enters the IDLE mode and waits in the local eNB cell.
  • FIG. 21 is a diagram for explaining a sequence example of the mobile communication system when the solution of the first embodiment is used.
  • FIG. 21 shows a sequence in which the UE periodically transmits a TAU. That is, FIG. 21 shows an example of the state transition represented by the arrow 1805 in FIG.
  • the UE After the sequence shown in FIG. 19 or the sequence shown in FIG. 20 is executed, the UE enters the IDLE mode in step ST2101, and after the local eNB starts the cell DTX in the DRX cycle in step ST2111, in step ST2102, The TA update sequence shown in FIG. 20 is executed. Thereafter, the TA update sequence in step ST2102 is repeated at a predetermined TA update cycle.
  • the local eNB can recognize that the UE has moved from the cell area to the outside of the cell area.
  • the local eNB may instruct periodic TAUs to UEs being served thereby. HeNB may instruct
  • the UE performs cell reselection in step ST2103, and if another eNB is determined as the best cell by reselection of the cell, the UE does not transmit a periodic TAU to the local eNB.
  • the other eNB transmits broadcast information to the UE.
  • the UE executes the TA Update sequence shown in FIG. 20 described above with another eNB in Step ST2104.
  • the local eNB determines whether or not TA Update is received from the UE in Step ST2113 at the next TA Update cycle. In the example illustrated in FIG. 21, the local eNB determines in step ST2113 that it has not received TA Update, and moves to step ST2114. In Step ST2114, the local eNB starts the extended cell DTX.
  • the case where the local eNB determines in the sequence of FIG. 21 that the UE that has been waiting in the cell area of the local eNB has moved out of the cell area is disclosed below.
  • the UE state monitoring unit 912 shown in FIG. 9 described above establishes an individual channel line last with the UE determined to be in the IDLE mode, and after the normal release, the time longer than the TAU period has elapsed.
  • the TAU is not executed in the TAU cycle from the UE that is determined to be in the IDLE mode in the UE state monitoring unit 912 shown in FIG.
  • FIG. 22 is a diagram for explaining a sequence example of the mobile communication system when the solution of the first embodiment is used.
  • FIG. 22 shows a sequence from the state in which the UE is waiting in the cell area of the local eNB to the CONNECTED mode by transmission. That is, FIG. 22 shows an example of the state transition indicated by the arrow 1806 in FIG.
  • step ST2201 the UE enters the IDLE mode and is in a standby state in the local eNB cell.
  • the UE performs a call origination operation.
  • Step ST2203 the UE requests random access (Random Access) to the local eNB.
  • step ST2205 the UE that has made a random access request enters the CONNECTED mode.
  • the local eNB determines that the requested random access is from a UE belonging to the CSG, the local eNB permits the access and sets an individual channel line through the processes of Step ST2206 and Step ST2207. Specifically, in step ST2206, the local eNB transmits a radio bearer setup message to the UE. When receiving the radio bearer setup message transmitted from the local eNB, the UE performs a process of setting an individual channel line in step ST2207, and transmits a radio bearer setup complete message to the local eNB.
  • the local eNB starts normal transmission in step ST2204 in order to start communication of the dedicated channel with the UE before the process of step ST2206.
  • user data is transmitted / received between the MME or HeNB-GW and the local eNB and UE.
  • FIG. 23 is a diagram for explaining a sequence example of the mobile communication system when the solution of the first embodiment is used.
  • FIG. 23 shows a sequence from when the UE enters the CONNECTED mode upon arrival from the standby state within the local eNB cell area. That is, FIG. 23 shows an example of the state transition indicated by the arrow 1806 in FIG.
  • step ST2301 the UE enters the IDLE mode and is in a standby state in the local eNB cell.
  • the MME or the HeNBGW transmits a call for the UE (hereinafter also referred to as “UE call”) to the local eNB.
  • UE call a call for the UE
  • the local eNB transmits paging information to the UE in Step ST2303.
  • the UE When the UE receives the paging information transmitted from the local eNB, the UE performs Paging information determination in Step ST2304. If the UE determines in the paging information determination process in step ST2304 that it is a call to the own device, the UE requests random access to the local eNB in step ST2305. In step ST2307, the UE that has requested random access enters the CONNECTED mode.
  • the local eNB determines that the requested random access is from a UE belonging to the CSG, the local eNB permits the access and sets an individual channel line through the processes of Step ST2308 and Step ST2309. Specifically, in step ST2308, the local eNB transmits a radio bearer setup message to the UE. When receiving the radio bearer setup message transmitted from the local eNB, the UE performs a process of setting an individual channel line in step ST2309, and transmits a radio bearer setup complete message to the local eNB.
  • the local eNB starts normal transmission in step ST2306 in order to start communication of the dedicated channel with the UE before the process of step ST2308.
  • transmission / reception of user data is performed between the MME or HeNB-GW and the local eNB and UE.
  • FIG. 24 is a diagram for explaining a sequence example of the mobile communication system when the solution of the first embodiment is used.
  • FIG. 24 shows a sequence from the state in which the UE communicates with the local eNB in the CONNECTED mode until the communication is disconnected and the IDLE mode is set. That is, FIG. 24 shows an example of the state transition represented by the arrow 1807 in FIG.
  • step ST2401 the UE enters the CONNECTED mode and communicates with the local eNB.
  • user data is transmitted and received between the MME or HeNB-GW and the local eNB and UE.
  • the UE When disconnecting communication with the local eNB from the UE, the UE transmits a release request message to the local eNB in Step ST2402. In response to the release request message, the local eNB transmits a radio bearer release message to the UE in Step ST2403. Although different from the example illustrated in FIG. 24, when disconnecting from the network, the local eNB transmits a radio bearer release message to the UE in Step ST2403 based on an instruction from the network.
  • the UE that has received the radio bearer release message transmits a radio bearer release complete message to the local eNB in step ST2404 as a response to the radio bearer release message.
  • a radio bearer release complete message to the local eNB in step ST2404 as a response to the radio bearer release message.
  • both the local eNB and the UE release the dedicated channel line, and the UE enters the IDLE mode in the cell area of the local eNB in step ST2406.
  • the local eNB starts a cell DTX having a DRX cycle.
  • a radio bearer release message is transmitted to a UE that is determined to be in the CONNECTED mode in the UE state monitoring unit 912, or (2) a radio bearer release complete message is received from the UE.
  • FIG. 25 is a location diagram illustrating a problem of the first modification of the first embodiment.
  • a plurality of local eNBs for example, three local eNBs (Local eNBs) 252-1, 252-2, and 252-3 constitute one tracking area (TA) 253, as shown in FIG. There is.
  • the three local eNBs illustrated in FIG. 25 are referred to as a first local eNB 252-1, a second local eNB 252-2, and a third local eNB 252-3.
  • the TA 253 is managed by the MME / S-GW unit 255, when the UE moves from outside the TA area to the TA area, the UE passes through one of the local eNBs 252-1, 252-2, and 252-3, and then the MME / S-GW. TAU is performed on the unit 255. For example, when TAU is performed through the first local eNB 252-1, the first local eNB 252-1 can know that the UE 251 is waiting in the IDLE mode, but the second and third local eNBs 252-2, 252 -3 cannot know that the UE 251 is in the IDLE mode.
  • the UE 251 even if the UE 251 reselects a cell within the TA 253, the UE 251 does not transmit a TAU to the reselected local eNB. Therefore, for example, even if the UE 251 selects and waits for the second local eNB 252-2 by reselecting the cell, the second local eNB 252-2 performs the cell DTX with the DRX cycle disclosed in the first embodiment. The problem that it is not possible occurs.
  • the MME / S-GW unit 255 in FIG. 25 knows that the UE 251 belonging to the CSG is located in the TA 253, a plurality of local eNBs belonging to the same TA being served as a standard, in FIG. 25, the first to third local eNBs The eNBs 252-1, 252-2, and 252-3 are notified of the presence of the UE 251 in the TA 253 (hereinafter sometimes referred to as “TA presence”).
  • TA presence the presence of the UE 251 in the TA 253
  • the MME / S-GW unit 255 knows that the UE 251 belonging to the CSG is out of the range of the TA 253, as a standard, a plurality of local eNBs belonging to the same TA, the first to third local in FIG.
  • the eNBs 252-1, 252-2, and 252-3 are notified that they are out of the TA range of the UE 251 (hereinafter sometimes referred to as “out of TA range”).
  • the local eNBs 252-1, 252-2, and 252-3 shown in FIG. 25 are notified that the UE 251 is in the TA area, that is, the UE 251 is within the TA 253 area, and the UE 251 is not communicating with its own device. Then, the cell DTX having the DRX cycle disclosed in the first embodiment is performed on the UE 251. In addition, when notified that the local eNB 252-1, 252-2, and 252-3 illustrated in FIG.
  • FIG. 26 is a location diagram for explaining a solution of the first modification of the first embodiment.
  • a plurality of local eNBs specifically, three local eNBs (Local-eNBs) 262-1, 262-2, and 262-3 constitute one tracking area (TA) 263-1, and a wide area
  • different eNBs hereinafter also referred to as “wide area eNB”
  • the TA 263-1 configured with the local eNBs 262-1, 262-2, and 262-3 is referred to as a first TA 263-1
  • the TA 263-2 configured with the wide area eNB is referred to as a second TA 263-2.
  • the management of the first TA 263-1 is performed by the HeNBGW 264 or the first MME / S-GW unit 265-1
  • the management of the second TA 263-2 is performed by the second MME / S-GW unit 265-2.
  • the UE 261 When the UE 261 moves from the first TA 263-1 to the second TA 263-2, the UE 261 performs TAU to the first MME / S-GW unit 265-1 through the wide area eNB 266.
  • the three local eNBs 262-1, 262-2, and 262-3 know that the UE 261 that has been in the first TA 263-1 that is its own TA has moved to another TA, for example, the second TA 263-2. If it can, it can be determined that the UE 261 is out of the first TA 263-1 range.
  • a specific example of operation will be described below using a sequence diagram.
  • the UE attaches with a TA including a local eNB
  • the UE moves from another TA into the TA including the local eNB and performs a TAU
  • the UE performs a detection with the TA including the local eNB
  • the UE may move from a TA including a local eNB to another TA and perform a TAU.
  • two local eNBs are used, specifically, a first local eNB and a second local eNB.
  • FIG. 27 is a diagram for explaining a sequence example of the mobile communication system when the solution of the first modification of the first embodiment is used.
  • FIG. 27 shows a sequence from when the UE is turned on, that is, when the UE is turned on, to the standby state in the cell of the local eNB.
  • the UE selects an initial cell in step ST2701. For example, the UE selects a cell having the best reception quality. In this operation example, it is assumed that the first local eNB is selected.
  • the UE receives the system information of the local eNB selected in Step ST2701, that is, the first local eNB. As a result, the UE can know parameters for random access to the first local eNB according to the contents of the system information (see Non-Patent Document 9).
  • Step ST2703 the UE performs PRACH transmission to the local eNB selected in Step ST2701, that is, the first local eNB. Since the system information acquired in step ST2702 includes the CSG-ID of the local eNB (see Non-Patent Document 9), in step ST2703, the UE has the CSG-ID of the local eNB selected in step ST2701 in the UE. PRACH transmission when it exists in the white list may be performed.
  • the first local eNB When receiving the PRACH transmitted from the UE, the first local eNB starts normal transmission in Step ST2704. Moreover, if UE performs PRACH transmission by step ST2703 as mentioned above, it will become CONNECTED mode in step ST2705.
  • Step ST2706 and Step ST2707 the first local eNB and the UE set up dedicated channel lines. Specifically, first, in step ST2706, the first local eNB transmits a radio bearer setup message instructing the setting of the dedicated channel line to the UE. When receiving the radio bearer setup message transmitted from the first local eNB, the UE performs processing for setting up an individual channel line in Step ST2707, and sends a radio bearer setup complete (Radio Bearer Setup Complete) message to the first local eNB. Send. Therefore, the first local eNB starts normal transmission in step ST2704 in order to start communication of the dedicated channel with the UE before the process of step ST2706. In Step ST2705, the UE enters the CONNECTED mode (also referred to as RRC_CONNECTED mode).
  • RRC_CONNECTED mode also referred to as RRC_CONNECTED mode
  • Step ST2706 and Step ST2707 the UE transmits an Attach request (Attach request) to the HeNBGW through the first local eNB in Step ST2708.
  • the HeNBGW that has received the Attach request notifies the UE of Attach approval (Attach Accept) through the first local eNB.
  • the UE that has received the Attach acknowledgment notifies the HeNBGW of Attach completion (Attach Complete) through the first local eNB.
  • Attach is successful (see Non-Patent Document 10).
  • Step ST2713 the first local eNB transmits a radio bearer release (RadioUEBearer Release) message to the UE.
  • the UE performs a process of releasing the dedicated channel line in Step ST2714, and sends a radio bearer release complete (Radio Bearer Release Complete) message to the first local eNB.
  • the radio bearer release complete message is transmitted in step ST2714 in this way, in step ST2716, the UE enters the IDLE mode and waits in the first local eNB cell.
  • Step ST2709-1 the HeNBGW or the MME transmits a TA area notification to the subordinate first local eNB in Step ST2710, and in Step ST2711, the TA area to the second local eNB Send a notification. This notifies the first and second local eNBs that the UE belonging to the CSG is in the TA.
  • the first local eNB and the second local eNB determine that if the UE belonging to the CSG that has been notified of the TA presence is not communicating with the own device, the UE is waiting in the IDLE mode, and the step In ST2712 and step ST2715, the cell DTX having the DRX cycle disclosed in the first embodiment is started. In this way, cells DTX with a DRX cycle can be performed in a plurality of local eNBs in the same TA.
  • the MME or HeNBGW that is the network control device is Then, it is determined whether or not a UE exists in the TA, and the determination result is notified to each local eNB.
  • each local eNB is notified from the MME or HeNBGW that the UE exists in its own TA, it determines whether or not it is communicating with the UE, and if it is determined that it is not communicating, Perform DTX.
  • a cell DTX having a DRX cycle can be performed.
  • the UE that is in the TA area and (2) the UE that has not set the dedicated channel is determined to be in IDLE mode.
  • FIG. 28 is a diagram for explaining a sequence example of the mobile communication system when the solution of the first modification of the first embodiment is used.
  • FIG. 28 shows an example of a sequence showing an operation of performing TAU by moving from another TA 263-2 to the TA 263-1 including the local eNB.
  • step ST2801 the UE performs cell reselection. For example, the UE selects a cell having the best reception quality. In this operation example, it is assumed that the first local eNB is selected.
  • Step ST2802 the UE receives the system information of the first local eNB selected in Step ST2801. Thereby, the UE can know the parameter for random access to the first local eNB, the tracking area code (TAC), and the CSG-ID of the first local eNB according to the contents of the system information.
  • TAC tracking area code
  • TAU is performed when a UE enters a new tracking area that is not in the registered TAI (Tracking Area Identity) list (see Non-Patent Document 10).
  • TAI Tracking Area Identity
  • the UE does not perform TAU. Therefore, the problem that local eNB cannot detect that UE moved to the cell area from the cell area outside or the cell of another eNB generate
  • the UE that has received the system information in step ST2802 in FIG. 28 determines whether or not the selected cell in step ST2801 is a local eNB. TAU will be performed independently. By this process, the local eNB can detect that the UE has moved out of the cell area or from the cell of another eNB to the cell area.
  • An indicator indicating whether or not the selected cell is a local eNB is newly provided in the system information.
  • the indicator included in the system information indicates that the selected cell is a local eNB
  • the UE determines that the selected cell is a local eNB, and the indicator indicates that the selected cell is a local eNB. If not, the UE determines that the selected cell is not a local eNB.
  • TAU may be performed regardless of the tracking area of the local eNB.
  • CSG-ID included in system information For example, if the CSG-ID is included, the UE determines that the selected cell is a HeNB, and if the CSG-ID is not included, the UE determines that the selected cell is not a HeNB.
  • csg-Indication included in system information. For example, if csg-Indication is “TRUE”, the UE determines that the selected cell is HeNB, and if csg-Indication is not “TRUE”, the UE determines that the selected cell is not HeNB.
  • hnb-Name included in system information. For example, if the hnb-Name is included, the UE determines that the selected cell is a HeNB. If the hnb-Name is not included, the UE determines that the selected cell is not a HeNB.
  • Step ST2803 the UE performs PRACH transmission to the first local eNB. Since the system information acquired in step ST2802 includes the CSG-ID of the local eNB, the UE performs PRACH transmission when the CSG-ID of the selected local eNB exists in the whitelist in the UE in step ST2803. You may do it.
  • the first local eNB judges that the PRACH is from a UE belonging to the CSG, the first local eNB permits access and sets up an individual channel line through the processes of Step ST2806 and Step ST2807. Specifically, first, in step ST2806, the first local eNB transmits a radio bearer setup message instructing the setting of the dedicated channel line to the UE. Upon receiving the radio bearer setup message transmitted from the first local eNB, the UE performs a process of setting an individual channel line in step ST2807, and transmits a radio bearer setup complete message to the first local eNB.
  • the first local eNB starts normal transmission in step ST2804 in order to start communication of the dedicated channel with the UE before the process of step ST2806.
  • Step ST2805 the UE enters a CONNECTED mode (also referred to as RRC_CONNECTED).
  • Step ST2806 When the dedicated channel is established in the processes of Step ST2806 and Step ST2807, the UE executes TA Update (TAU) to the HeNBGW or the MME through the first local eNB in Step ST2808.
  • TAU TA Update
  • Step ST2809 the HeNBGW that has received the TAU in Step ST2808 transmits a TA Update Accept to the UE through the first local eNB.
  • Step ST2809-1 the UE that has received TA Update Accept in Step ST2809 transmits TA Update Complete to the HeNBGW through the first local eNB. This makes TAU successful.
  • the first local eNB and the UE release the dedicated channel line.
  • the first local eNB transmits a radio bearer release message to the UE.
  • the UE performs a process of releasing the dedicated channel line in step ST2814, and transmits the radio bearer release complete message to the first local eNB.
  • the UE transmits a radio bearer release complete message in step ST2814 as described above, in step ST2816, the UE enters the IDLE mode and waits in the first local eNB cell.
  • the HeNBGW or MME transmits a TA location notification to the subordinate first local eNB in step ST2810, and in step ST2811, the TA location to the second local eNB Send a notification.
  • the HeNBGW notifies the subordinate local eNB, that is, the first and second local eNBs in the example illustrated in FIG. 28, that the UE belonging to the CSG is in the TA.
  • the first local eNB and the second local eNB determine that if the UE belonging to the CSG that has been notified of the TA presence is not communicating with the own device, the UE is waiting in the IDLE mode, and the step In ST2812 and step ST2815, a cell DTX having a DRX cycle disclosed in Embodiment 1 is started.
  • the UE that is in the TA area and (2) the UE that has not set the dedicated channel is determined to be in the IDLE mode.
  • FIG. 29 is a diagram for explaining a sequence example of the mobile communication system when the solution of the first modification of the first embodiment is used.
  • Step ST2903 when the UE is requested to turn off the power, the UE performs PRACH transmission to the first local eNB in Step ST2903.
  • the first local eNB starts normal transmission in Step ST2904.
  • UE performs PRACH transmission by step ST2903 as mentioned above it will become a CONNECTED mode in step ST2905.
  • the UE sets the dedicated channel line by the processes of Step ST2906 and Step ST2907, and establishes the dedicated channel line with the first local eNB.
  • the first local eNB transmits a radio bearer setup message instructing the setting of the dedicated channel line to the UE.
  • the UE Upon receiving the radio bearer setup message transmitted from the first local eNB, the UE performs processing for setting up an individual channel line in Step ST2907, and sends a radio bearer setup complete (Radio Bearer Setup Complete) message to the first local eNB. Send.
  • a radio bearer setup complete Radio Bearer Setup Complete
  • Step ST2908 the UE transmits a Detatch request to the HeNBGW through the first local eNB.
  • the HeNBGW that has received the Detach request transmits Detach completion to the UE through the first local eNB. As a result, Detach is successful.
  • Step ST2913 the first local eNB transmits a radio bearer release message to the UE.
  • the UE performs a process of releasing the dedicated channel line in step ST2914, and transmits the radio bearer release complete message to the first local eNB.
  • the UE transmits a radio bearer release complete message in step ST2914 as described above, the UE performs a process of turning off the power in step ST2916.
  • the HeNBGW transmits a TA out-of-range notification to the subordinate first local eNB in Step ST2910, and transmits a out-of-TA notification to the second local eNB in Step ST2911. .
  • the HeNBGW notifies the subordinate local eNB, that is, the first and second local eNBs in the example illustrated in FIG. 29, that the UE belonging to the CSG is not located in the TA.
  • the first local eNB and the second local eNB determine that the UE belonging to the CSG to which the TA out-of-range notification has been made is not communicating with its own device, and determines that the UE is out of the cell range, and in step ST2912 and step ST2915, The extended cell DTX disclosed in the first mode is started.
  • a UE that is out of the TA range and (2) has not set a dedicated channel is determined to be out of range.
  • FIG. 30 is a diagram for explaining a sequence example of the mobile communication system when the solution of the first modification of the first embodiment is used.
  • FIG. 30 shows an example of a sequence showing an operation of performing TAU by moving from the TA 263-1 including the local eNB to another TA 263-2.
  • step ST3001 the UE performs cell reselection. For example, the UE selects a cell having the best reception quality. In this operation example, it is assumed that the eNB 266 is selected.
  • Step ST3002 the UE receives the system information of the eNB 266 selected in Step ST3001. As a result, the UE can know the parameter for random access to the eNB 266, the tracking area code (TAC), and the CSG-ID of the eNB 266 according to the contents of the system information.
  • TAC tracking area code
  • TAU is performed when the UE enters a new tracking area that is not in the registered TAI list (see Non-Patent Document 10).
  • the UE does not perform TAU. Therefore, the problem that the local eNB cannot detect that the UE has moved from the cell area to the outside of the cell area or to a cell of another eNB occurs.
  • the eNB selected by the cell reselection is the local eNB.
  • TAU is performed regardless of the tracking area.
  • the local eNB can detect that the UE has moved from the cell area to the outside of the cell area or a cell of another eNB.
  • a specific example of determining whether or not a cell that is in the service area (hereinafter sometimes referred to as a “service cell”) is a local eNB is disclosed below.
  • An indicator indicating whether or not the serving cell is a local eNB is newly provided in the system information.
  • the UE determines that the serving cell is a local eNB, and the indicator indicates that the serving cell is a local eNB. Is not indicated, the UE determines that the serving cell is not a local eNB.
  • TAU may be performed regardless of the tracking area of the eNB selected by cell reselection.
  • csg-Indication included in system information. For example, if csg-Indication is “TRUE”, the UE determines that the serving cell is a HeNB, and if csg-Indication is not “TRUE”, the UE determines that the serving cell is not a HeNB.
  • hnb-Name included in system information. For example, if the hnb-Name is included, the UE determines that the serving cell is a HeNB, and if the hnb-Name is not included, the UE determines that the serving cell is not a HeNB.
  • Step ST3003 the UE performs PRACH transmission to the eNB. If PRACH transmission is performed, UE will be in CONNECTED mode in step ST3004.
  • the eNB grants access through the PRACH, the eNB sets an individual channel line through the processes of Step ST3005 and Step ST3006. Specifically, first, in step ST3005, the eNB transmits a radio bearer setup message instructing setting of the dedicated channel line to the UE.
  • the UE When receiving the radio bearer setup message transmitted from the eNB, the UE performs processing for setting an individual channel line in step ST3006, and transmits a radio bearer setup complete message to the eNB.
  • Step ST3005 and Step ST3006 the UE passes the eNB to the MME / S-GW unit, specifically, the second MME / S-GW unit 265-2 in FIG. 26 in Step ST3007.
  • Send TA Update In Step ST3008, the MME / S-GW unit that has received TA Update in Step ST3007 transmits TA Update Accept to the UE through the eNB.
  • Step ST3022 the UE that has received TA Update Accept in Step ST3008 transmits TA Update Complete to the MME / S-GW unit via the eNB. This makes TAU successful.
  • Step ST3024 the eNB transmits a radio bearer release message to the UE.
  • the UE performs a process of releasing the dedicated channel line in step ST3025, and transmits a radio bearer release complete message to the eNB.
  • the radio bearer release complete message is transmitted in step ST3025 in this manner, in step ST3026, the UE enters the IDLE mode and waits in the eNB cell.
  • the MME / S-GW unit When the MME / S-GW unit confirms the success of the TAU in step ST3008 and step ST3022, in step ST3009 and step ST3023, the MME / S-GW unit transmits a TA presence notification to the eNB and the surrounding HeNBGW via the S1 interface. Thereby, the MME / S-GW unit notifies the eNB and the surrounding HeNBGW that the UE is in the TA.
  • the HeNBGW When receiving the TA presence notification from the MME / S-GW unit in Step ST3009, the HeNBGW knows that the UE is not located in the TA of its own device, and in Step ST3010 and Step ST3011, the subordinate first local eNB, 2 Send out-of-TA notification to the local eNB.
  • the TA outside notification may be performed from the MME to the first local eNB and the second local eNB.
  • the first local eNB and the second local eNB determine that the UE belonging to the CSG to which the TA out-of-range notification has been made is not communicating with the own apparatus, and in step ST3012 and step ST3013, The extended cell DTX disclosed in the first mode is started.
  • FIG. 25 it is determined that the UE 251 belonging to the CSG is within the TA 253, and all the local eNBs 252-1, 252-2, and 252-3 perform the cell DTX with the DRX cycle disclosed in the first embodiment. And
  • the UE 251 receives the PO of the first local eNB 252-1 and at the same time, the second local eNB 252-2 and the third local eNB 252 that are neighboring cells. -3 must be detectable by cell search. After detection, the UE 251 must be able to monitor the reception levels of the second local eNB 252-2 and the third local eNB 252-3.
  • the second local eNB 252-2 and the third local eNB 252-3 are executing the cell DTX of the DRX cycle disclosed in Embodiment 1, the second local eNB 252-2 and the third local eNB 252-3 are: Since neither SS nor PBCH is transmitted, there arises a problem that the UE 251 cannot detect the second local eNB 252-2 and the third local eNB 252-3 by the cell search.
  • FIG. 31 shows a local eNB transmission method in cell DTX having a DRX cycle for solving another problem of modification 1 of the first embodiment.
  • FIG. 31 is a timing chart illustrating an example of a base station transmission signal using the solution of the first modification of the first embodiment.
  • FIG. 31 shows a case where the first local eNB 252-1, the second local eNB 252-2, and the third local eNB 252-2 are executing a cell DTX with a DRX cycle.
  • the first local eNB 252-1 transmits a radio frame 3102 according to the transmission ON signal 3101.
  • the transmission is turned on at the timing of PO included in the paging frame (PF) 3103 but also the transmission is turned on at the timing of SS and PBCH in another radio frame different from the PF 3103. It is.
  • the second local eNB 252-2 and the third local eNB 252-3 also turn on transmission of SS and PBCH in different radio frames different from PO and PF.
  • transmission may be turned on at the timing of SS and PBCH included in the radio frame 3104 next to PO and PF.
  • the mobile terminal (UE) in IDLE can perform paging signal reception and neighboring cell search operations with a single reception circuit on operation. Therefore, the effect of reducing the power consumption of the mobile terminal can be obtained.
  • transmission is turned ON at the timing of SS and PBCH in the radio frame next to PO and PF will be described.
  • the UE is in the IDLE mode and is waiting in the cell of the first local eNB 252-1.
  • the UE receives the PO of the first local eNB 252-1 in the DRX cycle.
  • the UE performs a neighbor cell search following PO reception. Since the UE can receive the SS and PBCH of the first local eNB 252-1, the SS and PBCH of the second local eNB 252-2, the SS and PBCH of the third local eNB 252-2, the first local eNB 252-1
  • the second local eNB 252-2 and the third local eNB 252-3 can be detected.
  • the first local eNB 252-1, the second local eNB 252-2, and the third local eNB 252-2 transmit SS and PBCH, they also transmit RS simultaneously.
  • the UE can monitor the cell by measuring the RSRP of the RS of the first local eNB 252-1, the second local eNB 252-2, and the third local eNB 252-2 detected by the cell search.
  • a mobile terminal (UE) compatible with 3GPP Release 8 performs comparison of each cell using an RSRP value of RS in cell selection. Therefore, when SS and PBCH are transmitted in Modification 1 of Embodiment 1, the method of transmitting RS at the same time has the effect that a mobile communication system with excellent backward compatibility can be constructed. be able to.
  • the first local eNB 252-1, the second local eNB 252-2, and the third local eNB 252-2 transmit SS and PBCH in one radio frame. This period is divided into two radio frames and three radio frames. It may be long.
  • the first local eNB 252-1, the second local eNB 252-2, and the third local eNB 252-3 are radio frames following the PF, but do not transmit subframes other than SS and PBCH. Only the RS may be transmitted in subframes other than PBCH.
  • FIG. 32 is a location diagram illustrating a problem of the second modification of the first embodiment.
  • the first UE 3203 is waiting for PO 3204 to receive a paging signal in the IDLE mode
  • the second UE 3205 is outside the coverage 3202 of the local eNB 3201; Indicates that you are outside the cell range.
  • local eNB 3201 performs cell DTX with the DRX cycle disclosed in Embodiment 1 for first UE 3203.
  • the local eNB 3201 transmits neither SS nor PBCH, so the second UE 3205 is within the coverage 3202 of the local eNB 3201, that is, within the cell range. Nevertheless, there is a problem that the local eNB 3201 cannot be cell-searched.
  • the cell search of the local eNB 3201 cannot be performed in this way, the following problems occur. For example, when the second UE 3205 is switched from the power OFF state to the power ON state, or when moving from outside the coverage 3202 of the local eNB 3201, that is, when moving from outside the cell area to the cell area, within the coverage 3202 of the local eNB 3201, That is, although it exists in the cell area, it cannot be attached to the local eNB 3201, that is, the location cannot be registered.
  • the local eNB 3201 is selected by cell reselection even though it exists in the coverage 3202 of the local eNB 3201, that is, in the cell area. become unable. Also, for example, if the second UE 3205 is communicating with another base station, the local eNB 3201 cannot be handed over to the local eNB 3201 even though it is within the coverage 3202 of the local eNB 3201, that is, within the cell area.
  • FIG. 33 is a timing chart illustrating an example of a base station transmission signal using the solution of the second modification of the first embodiment.
  • FIG. 33 illustrates a transmission signal of the local eNB 3201 of FIG. 32 in the arrangement and state of the local eNB 3201 and UEs 3203 and 3205 illustrated in FIG.
  • the local eNB transmits a signal obtained by mixing the signal of the extended cell DTX described above and the signal of the cell DTX having the DRX cycle disclosed in the first embodiment.
  • the SS and PBCH are transmitted as signals of the extended cell DTX.
  • the SS is arranged in the first subframe # 0 and the sixth subframe # 5 in the radio frame (10 ms).
  • the PBCH is arranged in the first subframe # 0 in the radio frame (10 ms).
  • the signal of the cell DTX in the DRX cycle is, for example, the ninth subframe # 8 in the paging frame (PF) 3303 in the example of FIG. 33 among the radio frames constituting the downlink transmission signal 3302 of the local eNB. It is transmitted in the PO subframe.
  • the local eNB transmits the PDSCH and the accompanying PDCCH and RS as a signal of the cell DTX in the DRX cycle. When there is no paging information, there is no need to transmit PDSCH, so the local eNB transmits only RS.
  • the local eNB turns on the transmission operation at a cycle of 5 ms to transmit SS and PBCH, and turns on the transmission operation at a DRX cycle, specifically, a cycle of about 1 to 5 seconds, and accompanies the PDSCH.
  • PDCCH and RS are transmitted. That is, the transmission ON signal 3301 of the local eNB is transmitted in a period of 5 ms with a period of a subframe (about 1 ms) for transmitting SS and PBCH, and a DRX cycle, specifically, a cycle of about 1 to 5 seconds. Thus, it is transmitted during the period of the PO subframe (about 1 ms).
  • the local eNB can turn off the transmission operation and stop the transmission operation of the downlink transmission signal 3302.
  • the transmission cycle of SS and PBCH specifically, the 5 ms cycle corresponds to the first transmission cycle
  • the DRX cycle corresponds to the second transmission cycle.
  • the intermittent transmission (DTX) of the DRX cycle is only RS because there is no need to transmit the PDSCH and the accompanying PDCCH when there is no paging information.
  • the first UE 3203 in the IDLE mode in FIG. 32 can receive the RS at the timing of PO by transmitting the signal obtained by mixing the signal of the extended cell DTX and the signal of the cell DTX having the DRX cycle. Therefore, the paging signal from the local eNB 3201 can be monitored, and the deviation of the local frequency can also be measured.
  • the second UE 3205 outside the coverage 3202 of the local eNB 3201 that is, outside the cell area, can receive the SS and PBCH of the local eNB 3201 if it moves within the coverage 3202 of the local eNB 3201, that is, within the cell area. It is possible to perform a cell search for the local eNB 3201.
  • PO, SS, and PBCH are transmitted as the transmission state of the local eNB that is the base station.
  • a state has been added. This can be said to be a state in which the extension cell DTX 1702 in FIG. 17 and the cell DTX 1703 having a DRX cycle are mixed (hereinafter, referred to as “mixed DTX having an extension cell and a DRX cycle” in some cases).
  • FIG. 34 is a state transition diagram illustrating a solution of the second modification of the first embodiment.
  • the local eNB transmission state determination unit according to the second modification of the first embodiment includes a normal transmission 3401, an extended cell DTX3402, a DRX cycle cell DTX3403, and an extended state. It manages four states of mixed DTX 3404 of cell and DRX cycle.
  • the state of each UE is managed by the method of Embodiment 1, and the transmission state is managed by a combination of the states of a plurality of UEs.
  • the local eNB when there are a plurality of UEs registered in advance in the CSG, the local eNB operates as follows.
  • the SS and broadcast channel PBCH are intermittently transmitted in a cycle in which the SS is arranged in the radio frame, specifically in a 5 ms cycle. Send.
  • a DRX cycle specifically, a cycle of about 1 second to 5 seconds, and at least RS of the paging signal and RS Is transmitted intermittently.
  • At least one UE is in the IDLE mode, that is, in a standby state, at least one UE exists outside the cell range of the local eNB, and there is no UE communicating with the local eNB.
  • SS and PBCH are intermittently transmitted at a cycle in which the SS is arranged in the radio frame, and at least the paging signal and RS are intermittently transmitted at the DRX cycle.
  • the extended cell and the DRX Perform periodic mixed DTX.
  • the UE in IDLE mode can receive the RS at the timing of PO, so it can monitor the local eNB and measure the local frequency deviation.
  • the UE existing outside the cell area of the local eNB can receive the SS and PBCH transmitted from the local eNB when moving to the cell area, it is possible to perform a cell search for the local eNB. Therefore, when moving to the cell area, the position registration can be surely performed.
  • a local eNB can be selected by cell reselection. It can also be handed over to a local eNB.
  • FIG. 35 is a location diagram illustrating a solution of the second modification of the first embodiment.
  • FIG. 35 shows that two UEs, a first UE 3503 and a second UE 3505, are in IDLE mode and are listening in the coverage 3502 of the local eNB 3501.
  • the first UE 3503 receives the first PO 3504 and the second UE 3505 receives the second PO 3506.
  • the first PO 3504 and the second PO 3506 are transmitted at different timings (see Non-Patent Document 3). Accordingly, since the local eNB 3501 transmits the PO twice in the DRX cycle, the transmission time becomes longer and the power consumption becomes longer than when the first PO 3504 and the second PO 3506 are transmitted at the same timing. There is a problem of increasing.
  • the transmission signal of the local eNB is prevented from being turned ON a plurality of times in the DRX cycle, and the power consumption is avoided.
  • Disclosed is a method for suppressing an increase in the above.
  • a plurality of POs of a plurality of UEs are set to the same subframe.
  • a plurality of POs of a plurality of UEs are set in the same radio frame.
  • Non-Patent Document 3 An example of a method for transmitting a plurality of POs of a plurality of UEs in the same subframe or the same radio frame is disclosed below. The following method is not disclosed in Non-Patent Document 3.
  • the local eNB and the UE have a plurality of PO calculation formulas for the local eNB and other eNBs.
  • the UE determines whether or not the standby cell is a local eNB. If the UE is a local eNB, the UE uses the PO calculation formula for the local eNB. In the calculation formula of PO for local eNB, the same PO or PF is derived in all UEs. UE may judge whether it is a local eNB from the system information acquired at the time of cell reselection.
  • the local eNB and UE have a plurality of PO calculation formulas.
  • the calculation formula includes a calculation formula C1 in which UEs under the same eNB or local eNB derive the same PO or PF.
  • the eNB and the local eNB put an indicator of which PO calculation formula is used in the system information.
  • the local eNB transmits an indicator indicating the calculation formula C1 of the PO.
  • FIG. 36 is a location diagram illustrating a problem of the third modification of the first embodiment.
  • the local eNB 3601 in FIG. 36 corresponds to the extended cell DTX disclosed in Non-Patent Document 8.
  • the local eNB 3601 transmits only the SS and PBCH because there is no UE in the coverage 3602, that is, in the cell area.
  • the UE 3603 outside the coverage 3602, that is, outside the cell area or turned off enters the coverage 3602, that is, within the cell area, or is turned on within the coverage 3602, that is, within the cell area.
  • the UE 3603 When the UE 3603 detects the local eNB 3601 by cell search, it is determined by the standard that the UE 3603 attaches to the core network through the local eNB 3601 (Attach). The attachment procedure is as shown in FIG. The operation will be described below according to the sequence of FIG.
  • step ST2701 of FIG. 27 the UE selects an initial cell. For example, the UE selects a cell having the best reception quality. In this operation example, it is assumed that the first local eNB is selected.
  • Step ST2702 the UE receives the system information of the local eNB selected in Step ST2701, that is, the first local eNB. As a result, the UE can know parameters for random access to the first local eNB according to the contents of the system information (see Non-Patent Document 9).
  • the system information is composed of a master information block (Master Information Block: MIB) and a system information block (System Information Block: SIB).
  • MIB Master Information Block
  • SIB System Information Block
  • RACH Configuration RACH Configuration
  • the local eNB 3601 Since the local eNB 3601 performs the extended cell DTX of Non-Patent Document 8, it does not transmit the PDSCH carrying the SIB. Therefore, the UE that determines that the local eNB 3601 is the best cell in the initial cell selection cannot acquire the RACH setting of the local eNB 3601 and cannot randomly access the local eNB 3601. That is, the UE cannot attach to the core network through the local eNB 3601 and cannot receive a communication service.
  • the UE cannot perform random access, so TAU cannot be performed.
  • the TA including the cell determined to be the best cannot be selected, causing a problem that the communication service is deteriorated.
  • a method for solving the problem in the third modification of the first embodiment is disclosed below.
  • the local eNB when a UE registers with a local eNB as a CSG, the local eNB notifies the UE of the RACH setting in advance. The UE stores the notified RACH configuration in association with the local eNB.
  • a UE can be identified by a cell identification number (Physical Cell Identity: also called PCI) transmitted by SS (P-SS, S-SS), GCI, or information in MIB transmitted by PBCH.
  • PCI Physical Cell Identity
  • P-SS, S-SS S-SS
  • GCI information in MIB transmitted by PBCH.
  • the eNB subjected to cell search is determined so that it can be identified as a pre-registered local eNB.
  • the UE determines whether or not the detected base station is executing the extended cell DTX.
  • Four methods for determining the extended cell DTX are disclosed below.
  • an indicator indicating the extended cell DTX is placed in the MIB and determined by the value of the indicator.
  • an indicator indicating the extended cell DTX is placed in the SIB1 and determined by the indicator value.
  • the ratio of the signal strength of the signal that is not transmitted in the extension cell DTX to the signal that is transmitted in the extension cell DTX is measured, and the result is determined by a threshold. If it is less than the threshold value, it is determined as an extended cell DTX.
  • the signal that is not transmitted in the extended cell DTX is, for example, RS.
  • the signal transmitted in the extended cell DTX is, for example, SS.
  • the SIB2 is not successfully demodulated within a predetermined time, it is determined as the extended cell DTX.
  • FIG. 37 is a diagram for explaining a sequence example of the mobile communication system when the solution of the third modification of the first embodiment is used.
  • the example of the sequence which UE registers as CSG with local eNB is shown.
  • the UE transmits a CSG registration start request message to the local eNB.
  • the local eNB that has received the CSG registration start request message in Step ST3701 transmits a CSG registration start permission message to the UE.
  • the communication between the UE and the local eNB performed in the processing of step ST3701 and step ST3702 may be performed using any means of a wireless line, infrared rays, and wired connection, and is performed using means other than these. Also good.
  • step ST3703 the local eNB and the UE that are currently registering CSG exchange information necessary for CSG registration.
  • the local eNB transmits parameters and RACH settings necessary for random access to the UE in Step ST3704.
  • Step ST3705 the UE stores the CSG ID being registered in association with the RACH setting and the cell identification number received in Step ST3704.
  • the local eNB transmits a CSG registration start completion message to the UE in Step ST3706.
  • the owner of the local eNB makes a CSG registration request using a separate communication network.
  • the CSG registration permission is notified from the host system to the UE via the local eNB. It is assumed that the CSG registration permission includes parameters necessary for random access and RACH settings.
  • the UE stores the CSG ID of the registered local eNB in association with the received RACH setting and cell identification number.
  • FIG. 38 is a diagram for explaining a sequence example of the mobile communication system when the solution of the third modification of the first embodiment is used.
  • the local eNB is executing the extended cell DTX, and transmits an SS to the UE in step ST3812.
  • step ST3801 the UE that has received the SS transmitted from the local eNB in step ST3812 performs initial cell selection or cell reselection. For example, the UE selects a cell having the best reception quality. In this operation example, it is assumed that a local eNB is selected.
  • step ST3813 the local eNB transmits the PBCH to the UE.
  • Step ST3802 the UE that has received the PBCH transmitted from the local eNB in Step ST3813 acquires the system information (MIB, SIB1) of the local eNB selected in Step ST3801.
  • Step ST3803 the UE determines whether or not the base station, in this operation example, the local eNB is executing the extended cell DTX.
  • the method of determining the expansion cell DTX in step ST3803 may be any of the four methods (1) to (4) described above.
  • step ST3803 If the UE determines in step ST3803 that the base station detected in step ST3801, that is, the local eNB is not executing the extended cell DTX, the UE moves to step ST3807, and in step ST3807, performs a system according to a normal procedure. SIB2 is acquired as information. Thereby, it is possible to know a parameter for random access to the detected base station (see Non-Patent Document 9).
  • step ST3808 the UE determines the RACH configuration from SIB2 acquired in step ST3807.
  • Step ST3803 if the UE determines that the base station detected in Step ST3801, that is, the local eNB is executing the extended cell DTX, the UE moves to Step ST3804.
  • the UE determines whether or not the cell identification number (CSG-ID, PCI, GCI, etc.) of the local eNB detected in the cell search of Step ST3801 matches the identification number of the registered local eNB. To do.
  • Step ST3804 when determining that the cell identification number of the local eNB detected by the cell search does not match the identification number of the registered local eNB, the UE ends all the processes.
  • Step ST3804 If it is determined in step ST3804 that the cell identification number of the local eNB detected in the cell search matches the identification number of the registered local eNB, the UE moves to step ST3805.
  • Step ST3805 the UE determines the RACH setting from the cell identification number. More specifically, the RACH setting stored in association with the cell identification number is determined as a parameter for randomly accessing the detected base station.
  • step ST3806 the UE performs PRACH transmission to the local eNB.
  • the detected base station is randomly accessed, and when access is permitted, an individual channel line is set.
  • the local eNB when a UE is registered, the local eNB notifies the UE of parameters necessary for random access with the UE. Thereby, even if the local eNB selected by the cell selection is executing the extended cell DTX, the UE can randomly access the base station that has specified the RACH setting.
  • the UE When the UE is powered on from the power-off state, it can be attached to the core network through the local eNB selected by cell selection, and can receive a communication service.
  • the UE When the UE re-selects a local eNB with a different TA due to movement, the quality of communication service can be maintained by selecting a TA including the cell determined to be the best and performing TAU.
  • a base station for example, eNB or local eNB receives a specific uplink transmission, it transmits a physical downlink shared channel (PDSCH) carrying a system information block (SIB) including parameters necessary for random access for a certain period of time.
  • PDSCH physical downlink shared channel
  • SIB system information block
  • the specific uplink transmission is one in which parameters for uplink transmission are known or quasi-statically determined by the mobile communication system. When it is determined semi-statically, it may be notified when changing from a serving cell to a mobile terminal (UE) or periodically.
  • Specific examples of parameters for uplink transmission include radio resources (frequency, time, etc.), initial transmission power, transmission data (sequence, etc.), modulation scheme, and the like.
  • the specific uplink transmission may be a specific PRACH.
  • FIG. 39 is a diagram for explaining a sequence example of the mobile communication system in the case where the solution of the third modification of the first embodiment is used.
  • the local eNB is executing the extended cell DTX in Step ST3911, and transmits the SS to the UE in Step ST3912.
  • Step ST3901 the UE that has received the SS transmitted from the local eNB in Step ST3912, performs initial cell selection or cell reselection. For example, the UE selects a cell having the best reception quality. In this operation example, it is assumed that a local eNB is selected.
  • step ST3913 the local eNB transmits the PBCH to the UE.
  • Step ST3902 the UE that has received the PBCH transmitted from the local eNB in Step ST3913 acquires the system information (MIB, SIB1) of the local eNB selected in Step ST3901.
  • Step ST3903 the UE determines whether or not the base station selected in Step ST3901, that is, the local eNB is executing the extended cell DTX.
  • the method of determining the expansion cell DTX in step ST3903 may be any of the four methods (1) to (4) described above.
  • Step ST3903 when the UE determines that the base station detected in Step ST3901, that is, the local eNB is not executing the extended cell DTX, the UE moves to Step ST3905, and acquires SIB2 according to a normal procedure in Step ST3905. Thus, it is possible to know parameters for random access to the detected base station (see Non-Patent Document 9).
  • Step ST3903 When the UE determines in step ST3903 that the base station detected in step ST3901, that is, the local eNB is executing the extended cell DTX, the UE moves to step ST3904, and in step ST3904, the PRACH requesting the necessary SIB2 is transmitted. Send to local eNB.
  • Step ST3905 the local eNB that has received the PRACH transmitted from the UE in Step ST3904 resumes transmission of the requested PDCCH and PDSCH carrying the SIB2 to the UE.
  • the UE acquires SIB2 by receiving SIB2 transmitted from the local eNB in Step ST3905, and can know parameters for random access to the detected base station.
  • Step ST3906 the UE determines the RACH setting from the SIB2 received in Step ST3905.
  • step ST3907 the UE performs PRACH transmission to the local eNB.
  • the detected base station is randomly accessed, and when access is permitted, an individual channel line is set.
  • the UE can randomly access the base station specifying the RACH setting.
  • the UE can be attached to the core network through the local eNB selected by cell selection, and can receive a communication service.
  • the UE selects a local eNB with a different TA by cell reselection due to movement, the quality of communication service can be maintained by selecting the TA including the cell determined to be the best and performing TAU. .
  • the present modification can be applied even when the base station is an eNB.
  • the same effect as the example can be obtained.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Dans un système de communication d'unité mobile de l'invention, même lorsqu'un dispositif terminal mobile (équipement d'utilisateur (UE)) dans un état non occupé est présent, la consommation d'énergie dans un noeud de réseau peut être réduite efficacement. Lorsque l'UE est dans l'état non occupé, un dispositif de station de base (72) transmet au moins un signal de référence pendant une période pendant laquelle un signal de radiomessagerie devrait être émis vers l'UE. En conséquence, l'UE peut recevoir le signal de référence, trouver le niveau de réception d'un signal transmis par le dispositif de station de base (72), et utiliser le niveau de réception pour déterminer la présence ou l'absence du signal de radiomessagerie.
PCT/JP2011/060257 2010-04-30 2011-04-27 Système de communication d'unité mobile WO2011136266A1 (fr)

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JP2018506907A (ja) * 2015-01-22 2018-03-08 日本テキサス・インスツルメンツ株式会社 ポイント・ツー・マルチポイントｎｌｏｓワイヤレスバックホールのための低オーバーヘッドシグナリング
JP2021073801A (ja) * 2015-01-22 2021-05-13 日本テキサス・インスツルメンツ合同会社 ポイント・ツー・マルチポイントｎｌｏｓワイヤレスバックホールのための低オーバーヘッドシグナリング
JP7339972B2 (ja) 2015-01-22 2023-09-06 テキサス インスツルメンツ インコーポレイテッド ポイント・ツー・マルチポイントｎｌｏｓワイヤレスバックホールのための低オーバーヘッドシグナリング
US10833832B2 (en) 2016-06-22 2020-11-10 Intel Corporation Communication device and a method for full duplex scheduling
US10756802B2 (en) 2016-11-17 2020-08-25 Huawei Technologies Co., Ltd. Communication method and terminal device
WO2018090631A1 (fr) * 2016-11-17 2018-05-24 华为技术有限公司 Procédé de communication et dispositif terminal

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